Big thanks to Fred Simmonds on his research for some of these numbers!
Thanks to PHS Online for some of these statistics.
1970 Pontiac Firebird
Comments: An all new Pontiac Firebird was introduced for 1970 and represented a new
high for Pontiac styling. The front bumper and grille were molded out of Endura
rubber and were painted the same color as the car to give it a bumperless appearance.
The sides sported rounded full wheel cut outs without any extra trim (the Camaro had
more squared off wheel cut outs). The suspension was revised and a rear stabilizer
bar was added. The Firebird lineup was reduced from six to four, and the convertible
was eliminated. At the bottom of the line up was the Base Firebird, whose Pontiac
250 I6 was replaced by a Chevy built 250 I6 rated at a meager 155bhp.
Next up was the Espirit, which featured the Pontiac 350 V8 rated at 255 bhp.
The Formula 400 featured a unique twin-scooped hood with a 400 V8 rated at 335 bhp.
At the top was the Trans Am, which was fitted with air dams across the bottom of the front and in front of the wheels. A large decklid spoiler and small spoilers in front of the rear wheels completed the package. These aero
pieces were claimed to generate 50 pounds of downforce on the front and rear of the
car at highway speeds. Trans Ams also received a rear facing shaker hood scope
to feed the standard Ram Air II engine. Optional on the Trans Am was the Ram Air IV
engine, whose output had increased to 370 bhp due to bigger ports, better heads,
swirl-polished valves, and an aluminum instake manifold. Only 88 copies were made.
Rarer still was the Ram Air V, an over-the-counter, special order engine that included
solid lifters and tunnel port heads and made up to 500 bhp. A four speed Hurst
shifter was standard, but a three speed Turbo Hydra-matic automatic was available.
Inside, complete instrumentation, including a tach turned on its side to red line at
12 o'clock just like a race car, completed the performance image. The Trans Am
featured one of the best tuned suspensions of any car (including the Corvette) and its
European styling gave it instant class. The Trans Am was now available in either Polar
White or Lucent Blue, with contrasting stripes, a relatively modest bird stencil at
the tip of the nose, and the words "Trans Am" across the rear spoiler.
Production: Trans Am: 3,196
Formula 400: 7,708
There were 689 RA Formulas made in 1970.
293 were M40 automatics
15 were M13 3 spds
192 were M20
189 were M21
Those with M21 got the 3.73 rear end and no A/C.
PONTIAC FORMULA PRODUCTION FIGURES
ENGINE
MANUAL
AUTOMATIC
TOTAL
WT
M21
n/a
458
WT
M20
n/a
1637
WT
M13
n/a
286
-
-
-
-
WS
M21
n/a
189
WS
M20
n/a
192
WS
M13
n/a
15
-
-
-
-
YZ
n/a
M40
293
-
-
-
-
YS
n/a
M40
4638
1970 Trans Am
L74 - RAM III
LS1 - SUPER DUTY RAM AIR
GRAND TOTAL
M13
M20
M21
TOTAL MANUAL
M40
TOTAL
M20
M40
TOTAL
NORWOOD
--
668
755
1423
1071
2494
41
23
64
2558
VAN NUYS
--
134
212
346
268
614
18
6
24
638
TOTAL
--
802
967
1769
1339
3108
59 (1)
29 (2)
88 (3)
3196
(1) California Emissions: 15 (2) California Emissions: 2 (3) All LS1 cars produced 7/70
1970 Trans Am Color Breakdown
Norwood
Van Nuys
Total
Polar White
1714
436
2150
Lucerne Blue
844
202
1046
AC & Manual Trans
175
48
223
AC & Auto Trans
578
187
765
Total AC Cars
753
235
988
(All AC TA's had L74 V8)
1970 Formula - W66
W66 (L78 Std. 400)
L74 - RAM AIR III
GRAND TOTAL
M13
M20
M21
TOTAL MANUAL
M40
TOTAL
M13
M20
M21
TOTAL MANUAL
M40
TOTAL
NORWOOD
241
1199
361
1801
2967
4768
10
146
149
305
221
526
2414
VAN NUYS
45
438
97
580
1671
2251
5
46
40
91
72
163
5294
TOTAL
286
1637
458
2381
4638
7019
15
192
189
396
293
689
7708
M13 = 3 sp. Manual M20 = 4 sp. Wide Ratio Manual M21 = 4 sp. Close Ratio Manual M40 = TH400 Automatic (no RA IV Formulas made)
1970 PONTIAC TRANS AM PRODUCTION FIGURES
ENGINE
MANUAL
AUTOMATIC
TOTAL
WS
1,769
-
1,769
WW
59
-
59
YZ
-
1,339
1,339
XP
-
29
29
-------------
-------
-------
-------
TOTAL
1,828
1,368
3,196
WT = L78 400 (manual transmission engine)
YS = L78 400 (automatic transmission engine)
WS = L74 400 "RAM AIR III" (manual transmission engine)
YZ = L74 400 "RAM AIR III" (automatic transmission engine)
WW = L67 400 "RAM AIR IV" (manual transmission engine)
XP = L67 400 "RAM AIR IV" (automatic transmission engine)
1970 Pontiac Firebird Trans Am 400 Ram Air III
Manual Transmission Engine Specifications
Engine Code
WS
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
10.5:1
Horsepower @ RPM
345@5000
Torque (Lb/Ft) @ RPM
430@3400
Head Casting
12
Carburetor
4-bbl
Carburetor - Federal
7040273
Carburetor - Calif
7040573
Intake Manifold
9799068
Camshaft
Part #
9779068
Lift, I/E
.410 / .413
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
288 / 302
Overlap - Degrees
63
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds
R 9799720
Exhaust Manifolds
L 478140
Distributor
1112024
1970 Pontiac Firebird Trans Am 400 Ram Air III
Automatic Transmission Engine Specifications
Engine Code
YZ
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
10.5:1
Horsepower @ RPM
345@5000
Torque (Lb/Ft) @ RPM
430@3400
Head Casting
12, 13
Carburetor
4-bbl
Carburetor - Federal
7040270
Carburetor - Calif
7040570
Intake Manifold
9799068
Camshaft
Part #
9779068
Lift, I/E
.410 / .413
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
288 / 302
Overlap - Degrees
63
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds
R 9799720
Exhaust Manifolds
L 478140
Distributor
1112009
1970 Pontiac Firebird Trans Am 40 Ram Air IV
Manual Transmission Engine Specifications
Engine Code
WW,WH
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
10.5:1
Horsepower @ RPM
370@5500
Torque (Lb/Ft) @ RPM
445@3900
Head Casting
614
Carburetor
4-bbl
Carburetor - Federal
7040273
Carburetor - Calif
7040573
Intake Manifold
9799084
Camshaft
Part #
9794041
Lift, I/E
.527 / .527
Rocker Arm Ratio
1.65:1
Duration I/E - Degrees
308 / 320
Overlap - Degrees
87
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds
R 9799721
Exhaust Manifolds
L 478141
Distributor
1112013
1970 Pontiac Firebird Trans Am 400 Ram Air IV
Automatic Transmission Engine Specifications
Engine Code
XP,XN
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
10.5:1
Horsepower @ RPM
370@5500
Torque (Lb/Ft) @ RPM
445@3900
Head Casting
614
Carburetor
4-bbl
Carburetor - Federal
7040270
Carburetor - Calif
7040570
Intake Manifold
9799084
Camshaft
Part #
9794041
Lift, I/E
.527 / .527
Rocker Arm Ratio
1.65:1
Duration I/E - Degrees
308 / 320
Overlap - Degrees
87
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds
R 9799721
Exhaust Manifolds
L 478141
Distributor
1112013
1971 Pontiac Firebird
Comments: 1971 saw little styling change for the Pontiac Firebird, with the addition of
high-back bucket seats being the major appearance change. In order to satisfy General Motors decree that all engines
had to run on unleaded gasoline to meet federal emission standards, the engine options
were significantly altered. A new 400 V8 rated at 300 bhp was added, but both 400 Ram Air
engines were dropped. In their place were two new 455 V8s, rated at 325 bhp and 335
bhp. The 455 HO engine was the only engine available in the Trans Am and borrowed the cylinder
heads (with larger combustion chambers) and the intake manifold from the 1970 Ram Air IV. The
Trans Am continued with its blue and white paint scheme, functional rear facing engine
shaker hood scoops, and aero body pieces. Although the 455 engines available in the Trans
Am were less powerful than the 1970 Ram Air IV engine, their 480 lb-ft of torque
and less tempermental nature made them easier to drive on the street and were one of the
high points in a time when performance was on the decline.
Performance: 455/335 (HO): 0-60 in 5.9 sec, 1/4 mile in 13.9 sec @ 103 mph.
1971 Pontiac Firebird Trans Am 455 CID H.O.
Manual Transmission Engine Specifications
Engine Code
WL, WC
Engine RPO
LS5
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.4:1
Horsepower @ RPM (Gross)
335@4800
Horsepower @ RPM (Net)
310@4800
Torque (Lb/Ft) @ RPM (Gross>
480@3600
Torque (Lb/Ft) @ RPM (Net)
410@3600
Head Casting
197
Carburetor
4-bbl
Carburetor - Federal
7041267, 7041273
Camshaft
Part #
9779068
Lift, I/E
.408 / .406
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
288 / 302
Overlap - Degrees
87
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Distributor
1112073
1971 Pontiac Firebird Trans Am 455 CID H.O.
Automatic Transmission Engine Specifications
Engine Code
YE, YA
Engine RPO
LS5
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
10.5:1
Horsepower @ RPM (Gross)
335@4800
Horsepower @ RPM (Net)
310@4800
Torque (Lb/Ft) @ RPM (Gross)
480@3600
Torque (Lb/Ft) @ RPM (Net)
410@3600
Head Casting
197
Carburetor
4-bbl
Carburetor - Federal
7041268, 7041270
Camshaft
Part #
9779068
Lift, I/E
.527 / .527
Rocker Arm Ratio
1.65:1
Duration I/E - Degrees
308 / 320
Overlap - Degrees
87
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Distributor
1112073
1972 Pontiac Firebird
Comments: 1972 was a disasterous year for the Firebird. GM executives considered dropping the
Firebird altogether as sales fell drastically as the muscle car market collapsed, which was
worsened by a crippling 174 day strike at the only plant that produced Firebirds. Pontiac
executives were able to eventually save the Firebird and it continued, with very little
change from 1971, except that its engines were now rated in net SAE numbers. Pontiac's
famous "honeycomb" wheels also made their first appearance in 1972.
Production: Trans Am: 1,286
Formula: 5,249 (PMD has a report that shows 5250 Total)
Formula Breakdown:
Honeycomb grille pattern (previous were square)
New optional "Unitized" electronic ignition
Essentially same engines with new lower "net" HP
ratings
No L75 regular 455
175 horsepower (L30) 350 engine (2544 made)
250 horsepower (L78) 400 engine (2429
made)
300 horsepower (LS5) 455HO engine (276
made)
5249 total produced (PMD has a report that shows 5250 Total)
1972 Pontiac Firebird Trans Am HO 455 CID
Manual Transmission Engine Specifications
Engine Code
WD, WM
Engine RPO
LS5
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.4:1
Horsepower @ RPM
300@4000
Torque (Lb/Ft) @ RPM
4150@3200
Head Casting
7F6
Carburetor
4-bbl
Carburetor - Federal
7042273
Intake Manifold
488945
Camshaft
Part #
9779068
Lift, I/E
.408 / .406
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
288 / 302
Overlap - Degrees
63
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Distributor
1972 Pontiac Firebird Trans Am HO 455 CID
Automatic Transmission Engine Specifications
Engine Code
YB, YE
Engine RPO
LS5
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.4:1
Horsepower @ RPM
300@4000
Torque (Lb/Ft) @ RPM
415@3200
Head Casting
7F6
Carburetor
4-bbl
Carburetor - Federal
7042270
Intake Manifold
488945
Camshaft
Part #
9779068
Lift, I/E
.408 / .406
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
288 / 302
Overlap - Degrees
63
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Distributor
1973 Pontiac Firebird
Comments: 1973 saw some significant new changes to the Firebird, including a new eggcrate
grille and a revised front bumper. Engine ratings were down again, with the 350 rated at a
mere 150 bhp and the 400 at 250 bhp. But two things would save the Firebird and firmly
establish Pontiac as the performance manufacturer during the dark days of the 1970s. The
first was the introduction of a new Super Duty 455 V8 (SD-455). "Super Duty" was the name
Pontiac used on its high performance (i.e. race ready) engines in the early 1960's, and
the Super Duty 455 was a street legal race prepped engine. All SD-455's were hand
assembled, and had a reinforced block, casting provisions for a cam driven dry sump on back of the block, special cam shaft, aluminum forged pistons, oversize
valves and header-like exhaust manifolds. Pontiac originally rated the SD-455 engines at a stout
310 bhp and 390 lb-ft, but experts agreed that it was closer to 370 bhp. The camshaft wouldn't pass emissions so they put a milder cam in with a 290 HP rating. This level of
engine ratings were unheard of in an era when other manufacturer's engines' output
were falling dramatically, and the Firebird became the only true performance car remaining
in the market. Unfortunately, Super Duty engines were expensive and therefore rare; only
252 Trans Am's and 43 Formula 455's received the SD-455 engine. The second major coup
for the Firebird was the introduction of a new Firebird decal on the Trans Am, which
covered almost the entire hood and was quickly nick-named "the screaming chicken,"
which added to the excitement and popularity of the entire Firebird lineup. Sales
of the Firebird and Trans Am were up dramatically, ensuring their survival.
Production: Trans Am: 4,802
Formula: 10,166
Formula Breakdown:
New similar nose with recessed grilles
Slight extension of rear bumper (5MPH bumper requirement)
Engine compartment reinforcing bars (5MPH again)
New "horsecollar" custom bucket option with
plusher door panels
533 Formulas had the Ram Air hood
New side stripe option
175 horsepower (L30) 350 engine (4771 made)
230 horsepower (L78) 400 engine (4622 made)
250 horsepower (L75) 455 (return of D-Port 455) (730 made)
310 horsepower (lS2) 455 Super Duty (43 made)
10,166 total produced (43 Super Duty)
PONTIAC FORMULA PRODUCTION FIGURES
MODEL
MANUAL
AUTOMATIC
TOTAL
Formula 350
?
?
4,771
Formula 400
?
?
4,622
Formula 455
227
503
730
Formula 455 SD
10
33
43
----
----
----
----
Total Firebird Formula
237
536
10166
For the 73 TA SD-455 cars and all 74 SD-455 cars, color and option numbers are not available.
1973 Pontiac Firebird Trans Am 455 CID
Manual Transmission Engine Specifications
Engine Code
WT, WW, ZZ, ZE
Engine RPO
L75
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.0:1
Horsepower @ RPM
250@4000
Torque (Lb/Ft) @ RPM
3700@2800
Head Casting
4X
Carburetor
4-bbl
Carburetor - Federal
7043273
Intake Manifold
497244
Camshaft
Part #
Lift, I/E
.410 / .414
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1973 Pontiac Firebird Trans Am 455 CID
Automatic Transmission Engine Specifications
Engine Code
X7, XE, XL, XM, YA, YC, YD
Engine RPOv
L75
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.0:1
Horsepower @ RPM
250@4000
Torque (Lb/Ft) @ RPM
370@2800
Head Casting
4X
Carburetor
4-bbl
Carburetor - Federal
7043262, 7043272
Intake Manifold
497244
Camshaft
Part #
Lift, I/E
.410 / .414
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1973 Pontiac Firebird Trans Am 455 CID Super Duty
Manual Transmission Engine Specifications
Engine Code
ZJ, W8
Engine RPO
LS2
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.4:1
Horsepower @ RPM
290@4000
Torque (Lb/Ft) @ RPM
390@3600
Head Casting
16, 485216
Carburetor
4-bbl
Carburetor
7043273
Intake Manifold
497245, 494405, 495107
Camshaft
Part #
493323
Lift, I/E
.410 / .410
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
301 / 313
Overlap - Degrees
76
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds- Right
490802
Exhaust Manifolds- Left
490803
Distributor
1973 Pontiac Firebird Trans Am 455 CID Super Duty
Automatic Transmission Engine Specifications
Engine Code
XD, X8
Engine RPO
LS2
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.4:1
Horsepower @ RPM
290@4000
Torque (Lb/Ft) @ RPM
390@3600
Head Casting
16, 485216
Carburetor
4-bbl
Carburetor
7043270
Intake Manifold
497245, 494405, 495107
Camshaft
Part #
493323
Lift, I/E
.410 / .410
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
301 / 313
Overlap - Degrees
76
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifolds- Right
490802
Exhaust Manifolds- Left
490803
Distributor
1974 Pontiac Firebird
Comments: For 1974 gone was the Endura bumper, replaced by
new, Federally mandated, fiberglass front end with a slight wedge shape and rubber covered
5 mph bumpers. The chrome rear bumper was also gone, replaced by rubber
bumpers. Engine ratings dropped again with the Trans Am's base 400 V8 engine rated at
225 bhp. But for a mere $57, buyers could order the 250 bhp 455 V8, which received a
10 lb-ft boost to 380 lb-ft, but which came only with an automatic transmission. The
mighty Super Duty 455 V8 was also available for an additional $578 and were unchanged from
the year before. All V8s included true dual exhausts, which made their last
appearance on the Firebird. Also available for the last time on the 1974 Firebirds
were the Muncie 4-speed manual transmission and the TurboHydramatic 400 automatic
transmission. This would also be the last year of the Super Duty engines.
Production: Trans Am: 10,255 - Super Duty 455: 943
Formula: 14,519 - Super Duty 455: 57
Formula Breakdown:
Radically redesigned front and rear with integrated bumpers
Wide rear taillights
Same engine ratings with the Super Duty now rated at 290 horsepower
Now standard power steering
Radial Tuned Suspension option
1,478 Formulas were produced with Ram Air (functional hood)
* 23 THM400 and 2 M21 accounted for so far in 455 SD Registry
PONTIAC SD-455 ENGINE PRODUCTION FIGURES
MODEL
4-SPEED
AUTOMATIC
TOTAL
1973 Firebird Trans Am
72
180
252
1973 Firebird Formula
10
33
43
1974 Firebird Trans Am
212
731
943
1974 Firebird Formula
n/a
n/a
57
TOTAL
n/a
n/a
1,295
Figures obtained from official
Pontiac Historical Society figures.
In 1973, 4,802 Firebird Trans Ams were produced.
In 1974, 10,255 Firebird Trans Ams were produced.
For complete production figures for 1973 and 1974
Pontiac Firebirds
.
1973-74 PONTIAC FIREBIRD TOTAL PRODUCTION FIGURES
YEAR
Firebird
Esprit
Formula
Trans Am
Total
1973
14,096
17,249
10,166
4,802
46,313
1974
26,372
22,583
14,519
10,255
73,729
Figures obtained from official
Pontiac Historical Society figures.
1974 Pontiac Firebird Trans Am 400 CID Manual Transmission Engine Specifications
Engine Code
WT, WW, ZZ, ZE
Engine RPO
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.0:1
Horsepower @ RPM
225@4000
Torque (Lb/Ft) @ RPM
330@2800
Head Casting
4X
Carburetor
4-bbl
Carburetor - Federal
7043263
Intake Manifold
495106
Camshaft
Part #
9779067
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
55
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1974 Pontiac Firebird Trans Am 400 CID
Automatic Transmission Engine Specifications
Engine Code
X7, XE, XL, XM, YA, YC, YD
Engine RPO
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.0:1
Horsepower @ RPM
225@4000
Torque (Lb/Ft) @ RPM
330@2800
Head Casting
4X
Carburetor
4-bbl
Carburetor - Federal
7044263, 7044266,7043263, 7043266
Intake Manifold
495106
Camshaft
Part #
9779066
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 282
Overlap - Degrees
55
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1974 Pontiac Firebird Trans Am 455 CID
Automatic Transmission Engine Specifications
Engine Code
AU, A4, YW, YY, Y9, ZU, ZW, Z4
Engine RPO
L75
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.0:1
Horsepower @ RPM
250@4000
Torque (Lb/Ft) @ RPM
380@2800
Head Casting
4X
Carburetor
4-bbl
Carburetor - Federal
7044262
Carburetor - High Altitude
7044272
Intake Manifold
495106
Camshaft
Part #
9779067
Lift, I/E
.410 / .414
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1974 Pontiac Firebird Trans Am 455 Super Duty
Manual Transmission Engine Specifications
Engine Code
W8
Engine RPO
LS2
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.3:1
Horsepower @ RPM
290@4000
Torque (Lb/Ft) @ RPM
395@3200
Head Casting
16
Carburetor
4-bbl
Carburetor
7044273
Intake Manifold
495107
Camshaft
Part #
493323
Lift, I/E
.410 / .410
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
301 / 313
Overlap - Degrees
76
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifold - Right
490802
Exhaust Manifold - Left
490803
Distributor
1112205
1974 Pontiac Firebird Trans Am 455 Super Duty
Automatic Transmission Engine Specifications
Engine Code
Y8
Engine RPO
LS2
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
8.3:1
Horsepower @ RPM
290@4000
Torque (Lb/Ft) @ RPM
395@3200
Head Casting
16
Carburetor
4-bbl
Carburetor
7044270
Intake Manifold
495107
Camshaft
Part #
493323
Lift, I/E
.410 / .410
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
301 / 313
Overlap - Degrees
76
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.77"
Exhaust Manifold - Right
490802
Exhaust Manifold - Left
490803
Distributor
1112205
1975 Pontiac Firebird
Comments: In what had been a sea of pony car competitors, the Pontiac Firebird was all alone
for 1975. The Camaro Z28, AMC Javelin, Plymouth Barracuda, and Dodge Challenger all were
discontinued. The Ford Mustang was now offered on a Pinto platform and boasted a top engine
offering of a 105 bhp 2.8 liter V6! The 1975 Firebird featured a new front end (it's third
in three years) and a much improved rear window, which greatly improved visibility. The
instrument panel stayed the same, but the old 160 mph speedometer was replaced by a new 100 mph
unit, to better reflect the new times. The base 400 cid V8 Trans Am engine put out a pitiful 185 bhp,
but still cranked out 310 lb-ft of torque. But the big news was what was lost: No
Super Duty 455 engine, no Turbo-Hydramatic 400 automatic transmission, no Muncie Four-Speed Manual
Transmission, no true dual exhausts. The main culprit: the new Federally mandated Catalytic
Converters. The 455 V8 was re-introduced mid-year in "H.O." guise, but it was just the
455 engine from the Bonneville and produced only 200 bhp.
1975 Pontiac Firebird Trans Am 400 CID
Manual Transmission Engine Specifications
Engine Code
WT
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
310@1600
Head Casting
5C 6X after mid-year
Carburetor
4-bbl
Carburetor - Federal
7045263
Intake Manifold
495106
Camshaft
Part #
9779066
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 283
Overlap - Degrees
59
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1975 Pontiac Firebird Trans Am 400 CID
Automatic Transmission Engine Specifications
Engine Code
YS
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
310@1600
Head Casting
5C 6X after mid-year
Carburetor
4-bbl
Carburetor - Federal
7045274
Carburetor - California
7045564
Intake Manifold
495106
Camshaft
Part #
9779066
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 283
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1975 Pontiac Firebird Trans Am 455 CID
Manual Transmission Engine Specifications
Engine Code
WX
Engine RPO
L75
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
7.6:1
Horsepower @ RPM
200@3500
Torque (Lb/Ft) @ RPM
330@2000
Head Casting
6H
Carburetor
4-bbl
Carburetor - Federal
7045263
Intake Manifold
496140
Camshaft
Part #
9779067
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1112923
1976 Pontiac Firebird
Comments: 1976 would be the last year of the 455 engine, and the first year of available
T-Tops. All Firebirds received new more angular bumpers which improved their appearance,
and Pontiac introduced the very popular Black-and-Gold Special Edition Trans Am which quickly
became one of the most famous Trans Am's of all time.
The Limited Edition Trans Am was introduced in February at the Chicago Automobile Show.
The LE Trans Am had Starlight black finish with gold striping, along with gold interior accents,gold honeycomb wheels, a 50th anniversary badge,plus more, including T-Tops.
The cars were shipped to Hurst Corp. in Michigan.
But due to problems with the Hurst roof treatment only about 25 % of the LE cars had T-Tops.
The total production was only 2590 with only 643 LE Trans Am's having the T-Tops.
The installation of the optional 455 was less than 500 for the LE Trans Ams, only 110 455 engined LE Trans Am with T-Tops were made.
This would be the first year that
over 100,000 Firebirds were sold.
1976 Pontiac Firebird Trans Am 400 CID
Manual Transmission Engine Specifications
Engine Code
WU
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
310@1600
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17056564
Camshaft
Part #
9779066
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 283
Overlap - Degrees
55
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1976 Pontiac Firebird Trans Am 400 CID
Automatic Transmission Engine Specifications
Engine Code
YS, Y9 or YZ
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
310@1600
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17056264
Camshaft
Part #
9779066
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 283
Overlap - Degrees
55
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1976 Pontiac Firebird Trans Am 455 CID H.O.
Manual Transmission Engine Specifications
Engine Code
WX
Engine RPO
L75
Displacement
455 CID
Bore x Stroke
4.1522" x 4.121"
Compression Ratio
7.6:1
Horsepower @ RPM
200@4000
Torque (Lb/Ft) @ RPM
330@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17056261
Camshaft
Part #
9779067
Lift, I/E
.407 / .407
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
273 / 289
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1112960
1977 Pontiac Firebird
Comments: 1977 saw a new "Batmobile" front end with quad square headlamps and ever more complex
engine choices. The Chevy inline six was dumped for a Buick 231 cubic inch (3.8 liter) V6 as the
base engine. A new 301 (4.9 liter) V8 rated at just 135 bhp was available in Esprits and Formulas,
with the familiar 350 was optional. Trans Am's featured either a Oldsmobile 403 (6.6 liter) V8
or the Pontiac 400 (T/A 6.6) engine under their shaker hood. Meanwhile, Firebirds sold in
California had to make due with Chevy 305 and 350 V8s to meet the state's strict emission laws.
But 1977 would the year that firmly established the Firebird as the performance car of the 1970s.
Burt Reynolds drove a Black-and-Gold Special Edition Trans Am in the unexpected movie hit
"Smokey and the Bandit", that drove the Firebird's popularity (and sales) to new heights.
1977 Pontiac Firebird Trans Am 400 CID (Pontiac)
Automatic Transmission Engine Specifications
Engine Code
XA
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
180@3600
Torque (Lb/Ft) @ RPM
325@1600
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17057274
Intake Manifold
525355
Camshaft
Part #
527471
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1103269 w/2.92 & under axle ratio
Distributor
1103271 w/2.93 & higher axle ratio
1977 Pontiac Firebird Trans Am 403 CID (Oldsmobile)
Automatic Transmission Engine Specifications
Engine Code
U2, U3, VA, VB
Engine RPO
L80
Displacement
403 CID
Bore x Stroke
4.3512" x 3.385"
Compression Ratio
8.0:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
320@2200
Head Casting
554717
Carburetor
4-bbl
Carburetor - California
17057550 w/o Air Cond
Carburetor - California
17057553 w/ Air Conditioning
Carburetor - High Altitude
17057258
Intake Manifold
411990
Camshaft
Part #
562299
Lift, I/E
.440 / .440
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
2.00"
Exhaust Valve - Dia
1.50"
Distributor
1977 Pontiac Firebird Trans Am 400 CID T/A 6.6
Manual Transmission Engine Specifications
Engine Code
WA
Engine RPO
L78 / W72
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.1:1
Horsepower @ RPM
200@4000
Torque (Lb/Ft) @ RPM
330@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17057263
Intake Manifold
525355
Camshaft
Part #
549431
Lift, I/E
.365 / .404
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
274 / 298
Overlap - Degrees
62
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1977 Pontiac Firebird Trans Am 400 CID T/A 6.6
Automatic Transmission Engine Specifications
Engine Code
Y6
Engine RPO
L78 / W72
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.1:1
Horsepower @ RPM
200@4000
Torque (Lb/Ft) @ RPM
330@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17057266
Intake Manifold
525355
Camshaft
Part #
549112
Lift, I/E
.365 / .404
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
274 / 298
Overlap - Degrees
55
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1978 Pontiac Firebird
Comments: Attempting to capitalize on its new found popularity, Pontiac offered a slew of
Special Edition Firebirds including a Gold Trans Am with brown accents and Blue "Sky Bird"
and Red "Red Bird" Firebirds. Sales soared to a record 187,294 units, including 93,341
Trans Am's.
Production: Total Firbirds: 187,285
Trans Am: 93,341
Formula: 24,346
810 W72 Formulas with 4-speed transmissions
1 According to an authority on 1977-78 W72's
John Witzke, no L78 (without W72) 400's or L80 403(Olds) came with M-21 manual transmissions.
1978 PONTIAC FORMULA/TA W72 PRODUCTION FIGURES
MODEL
MANUAL
AUTOMATIC
TOTAL
Base Trans Am (W72)
10,916
11,057
21,973
Trans Am Y88 (W72)
1,267
6,519
7,786
Trans Am Y84 (W72)
20
68
88
Trans Am Y82 (W72)
489
2,856
3,345
Formula (W72)
810
884
1,694
-------------
-----------
-----------
-----------
Total W72 TRANS AM/FORMULA
13,502
21,384
34,886
1978 Pontiac Firebird Trans Am 400 CID (Pontiac)
Automatic Transmission Engine Specifications
Engine Code
YA (early production)
Engine Code
YU (late production)
Engine RPO
L78
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
7.6:1
Horsepower @ RPM
180@3600
Torque (Lb/Ft) @ RPM
325@1600
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17058276 (early production)
Carburetor - Federal
17058278 (late production)
Camshaft
Part #
527471
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1103359
1978 Pontiac Firebird Trans Am 403 (Olds) Automatic Transmission Engine Specifications
Engine Code
U2, U3, VA, VB
Engine RPO
L80
Displacement
403 CID
Bore x Stroke
4.3512" x 3.385"
Compression Ratio
8.0:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
320@2200
Head Casting
NA
Carburetor
4-bbl
Carburetor - California
17058553
Camshaft
Part #
562299
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
NA
Exhaust Valve - Dia
NA
Distributor
1103325
1978 Pontiac Firebird Trans Am 400 CID T/A 6.6
Manual Transmission Engine Specifications
Engine Code
WC
Engine RPO
L78 w/W72
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.1:1
Horsepower @ RPM
220@4000
Torque (Lb/Ft) @ RPM
320@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17058263
Camshaft
Part #
10003402
Lift, I/E
.395/.401
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
274 / 298
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1103315
1978 Pontiac Firebird Trans Am 400 CID T/A 6.6
Automatic Transmission Engine Specifications
Engine Code
X7
Engine RPO
L78 w/W72
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.0:1
Horsepower @ RPM
200@4000
Torque (Lb/Ft) @ RPM
320@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17058266
Camshaft
Part #
10003402
Lift, I/E
.395 / .401
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
274 / 298
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1103315
1979 Pontiac Firebird
Comments: As the 1970s drew to a close, the 1979 Pontiac Firebird received a new nose, with the
four rectangular headlights all in their own bezels, and the split grille was moved below
them. The rear end featured blackout panels disguising the taillights on Formula and Trans Am
models. All models also received some revised graphics. A special silver 10th Anniversary
edition Trans Am was sold in what would be the last year for the Pontiac 400 engine which were stockpiled from 1978.
1979 Pontiac Firebird Trans Am 301 CID T/A 4.9 Manual Transmission Engine Specifications
Engine Code
PWA, PWB
Engine RPO
L37
Displacement
301 CID
Bore x Stroke
4.00" x 3.00"
Compression Ratio
8.0:1
Horsepower @ RPM
150@4400
Torque (Lb/Ft) @ RPM
235@2200
Head Casting
01
Carburetor
4-bbl
Carburetor
17059271
Camshaft
Part #
527471
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
1.72"
Exhaust Valve - Dia
1.50"
Distributor
1103400
1979 Pontiac Firebird Trans Am 301 CID T/A 4.9 Automatic Transmission Engine Specifications
Engine Code
PX4, PX6, PXL, PXN, PXS, PXT, PXU, PXW
Engine RPO
L37
Displacement
301 CID
Bore x Stroke
4.00" x 3.00"
Compression Ratio
8.0:1
Horsepower @ RPM
150@4400
Torque (Lb/Ft) @ RPM
2450@xxxx
Head Casting
01
Carburetor
4-bbl
Carburetor
17059272
Camshaft
Part #
10007424
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
1.72"
Exhaust Valve - Dia
1.50"
Distributor
1103399
1979 Pontiac Firebird Trans Am 403 CID (Oldsmobile)
Automatic Transmission Engine Specifications
Engine Code
QE, QJ, QK, QL, Q6, TD, TE
Engine RPO
L80
Displacement
403 CID
Bore x Stroke
4.3512" x 3.385"
Compression Ratio
8.0:1
Horsepower @ RPM
185@3600
Torque (Lb/Ft) @ RPM
320@2200
Head Casting
NA
Carburetor
4-bbl
Carburetor - Federal w/o Air
17059250
Carburetor - Federal w/Air
17059253
Carburetor - High Altitude
17059258
Carburetor - California
17059553
Camshaft
Part #
562299
Lift, I/E
/
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
NA / NA
Overlap - Degrees
NA
Intake Valve Dia -
NA
Exhaust Valve - Dia
NA
Distributor
1103325
1979 Pontiac Firebird Trans Am 400 CID T/A 6.6
Manual Transmission Engine Specifications
Engine Code
PWH
Engine RPO
L78 w/W72
Displacement
400 CID
Bore x Stroke
4.1212" x 3.750"
Compression Ratio
8.1:1
Horsepower @ RPM
220@4000
Torque (Lb/Ft) @ RPM
320@2800
Head Casting
6X
Carburetor
4-bbl
Carburetor - Federal
17059263
Camshaft
Part #
10003402
Lift, I/E
.395/.401
Rocker Arm Ratio
1.5:1
Duration I/E - Degrees
274 / 298
Overlap - Degrees
54
Intake Valve Dia -
2.11"
Exhaust Valve - Dia
1.66"
Distributor
1103315
1980 Pontiac Firebird
Comments: Pontiac dropped its 400 V8 and
installed a new Turbo-charged 301 (4.9 liter) V8 as its top engine choice. The Turbo 4.9 was rated at 210 bhp.
A Pontiac Trans Am paced the Indianapolis 500 race that year. Sales dropped considerably.
The turbo package (listed on the order form as RPO LU8) was offered only with automatic transmission and a 3.08 axle and cost a reasonable $350 on Trans Ams and $530 on Formulas. The turbocharged engine met federal emissions standards, but wasn't available in California, although some were assembled there.
TRANS AM WORLD