Powertrain

Engine type Pontiac Big Block V-8 455 Super Duty
Displacement 7.5 l (455 ci)
Power 314 ps (310 bhp / 231 kw) @ 4000 rpm
Torque 529 Nm (390 lb-ft) @ 3600 rpm
Power / liter 42 ps (42 hp)
Transmission Muncie M20 and M22 4 Speed Manual (3.08 and 3.42 ratio)
Layout front engine, rear wheel drive

Performance
Top speed 250 kph (155 mph)
0 - 100 kph 5.4 s
0 - 60 mph 5.1 s
1/4 mile 13.5 s @ 104.4 mph

Comments (32)

User avatar


User avatar

Shaggy  3 months ago  

That's right.


User avatar

Kaki Yokisy   3 months ago  

It seems that Pontiac firebird trans am 455 heavy duty is 455ci 7.5i.


User avatar

santos  1 year ago  

tran sam are cool


User avatar

Fangio Man  3 years ago  

True classic...


User avatar

babak  3 years ago  

Ilove only 1971 chevy LT1 350 the best and fastest in america in original and stock class.


User avatar

74SD455TA  3 years ago  

Correction the SD registry shows about 125 1973 SD 455 T/A's. Not 250 as I had said earlier. There are about 250 1974 SD 455 T/A's registered


User avatar

SD455TA  4 years ago  

@Bijan. Thanks for your comment. Just to add, my SD is a radio delete with blockout plate and does not have the chicken on the hood (I never liked those). Life is too short not to have an SD. So few people will ever even see one in their lifetime let alone own or drive one. A comment I saw that you made previously is incorrect. The 73/74 SD engines were 100% identical. There was no difference in net horsepower. The cams were the same as was everything else in the engines. The reason you see 310HP posted for the 73 and 290 for the 74 is simply that it all the specs and literature went to print from Pontiac before the EPA mandated the cam change which brought the net HP to 290. Pontiac just left the print as it was at the original 310 number. So, the 73 also has 290HP stock. About learning the acceleration you spoke of, I did own a 74 Formula 400 brand new. It was a 2bbl car. Pretty but slow. Of course as a kid I did end up hot rodding it pretty extensively (never touched the bottom end) to where it would run in the 12's. You were able to quite well getting your legs under you in that 1970 Ram Air III car.


User avatar

Bijan  4 years ago  

@ 74SD455TA : Congratulations , White on white ... Excellent .
I owned a Blue 4-speed 1970 RA III TA when I was 18-19 , she was teaching me about the corners , under-steering and mid rev performance .


User avatar

74SD455TA  4 years ago  

to finish from the post below..walked into the local Pontiac dealer and have ordered a 74 SD. Actually receiving one is another topic. Only 2 things stopped me. One, I didn't have the money and two, I would have destroyed it as a 16 year old kid. To chime in about the Ram Air V, to the best of my knowledge, Pontiac never sold any of these to the public. Pontiac shut it down however it has been said that around 200 Ram Air V engines were sold from the dealers as crate engines. Other parts were rumored to have been sold over the counter at some Pontiac dealers. For the 73/74 SD's, according to the SD registry, there are about 250 74 SD's listed in various conditions and a similar number of 73's. Pontiac's RULE.


User avatar

74SD455TA  4 years ago  

I am the proud owner of a 74 SD 455TA. VIN #129978. It is 1 of 1 in the SD registry with white and white standard interior with Turbo 400. It is #'s matching with 22K original miles. It was important for me to own one that did not have A/C. The A/C was heavy, never worked all that well in those cars and you were not able to order it with the 3.42 gear ratio which did nothing but sacrifice performance. The engine has been re-done to specifications primarily the way Pontiac engineers envisioned it before the EPA clamped down on them and they had to tone it down. The cam is a Nunzi Ram Air IV style 470 lift and the carb has been rejetted to provide a more optimal air/fuel mixture. Naturally the EGR valve was rendered inoperative. Compression was left pretty much as is and stands at around 8.75. The only other modification has been the addition of a 2400 RPM stall speed. I do have a performance meter and have tested it on the street. Trap speeds come in around 115MPH at 5700RPM shift points. These engines are too rare to attempt to disintegrate at higher RPM's. The engine develops so much power that representative 1/4 times on street tires are impossible to obtain as you burn rubber all the way through about 1/2 of second gear while having a hard time keeping the car straight. With slicks low 12's would be the target. Should long tube headers be added along with a taller gear ratio of 3.90 or 4.10, the 11's should be doable. To think that when I was 16 I could have walked into


User avatar

Super8  4 years ago  

Something that i don't understand is why Chevy underrated Camaro ZL1 into 376 net Hp while all 3 Corvette ZL1 is overpowered into almost 500 Hp net @ 6000 rpm? Camaro underrated but Corvette no..... That's really disturbing.


User avatar

Super8  4 years ago  

@ Bijan: Pontiac had very brilliant engine in 69 to 70's. RA V make the 69 GTO run into 183 mph without even change it into long ratio. I believe it can make GTO reach 190-195 mph if fitted with long ratio 4 speed if the aero allow it. It completely outrun Corvette cuz it need tuned engine like ZL1 to run at that speed.


User avatar

Bijan  4 years ago  

@ Super8 : I completely agree with you , about some down rating horse power , Specially in 60' and early 70 from Mopar to Chevy to Ford and ...., But I never completely understand WHY ??
Anyway I see the L-88's in Lemans and , see the video from 1967 First lap of L-88 at Lemans , Amazing .... Dont care that GM told 430 hp or .... , in my opinion the 7 liter L-88's are brilliant fast cars , also RA IV's , RA V's and SD 455 emission cars .


User avatar

Bijan  4 years ago  

@ Super 8 : I heard from some SD owners , that Dyno tested and they say something from 355 to 371 SAE net hp for 74 SD with 301-311 Degrees Duration and some milder cam with 7000 rpm max speed .
but for 1973 that used Wilder cam durations of 308 degrees intake and 320 degrees Exhaust , opting for a .470 - inch lift instead of .520 , that used in RAM AIR V and they said the power from 370 to 400 SAE Net hp .
Extra high rev engine with 7.5 liter and 7500 rpm max , maybe 500 plus less than RA V mechanical lifter racer beast .
The 1973 SD455 is one of my all time favorite Classic high performance cars with 7.5 liter V8 and full street legal that ran on 91 octane fuel .


User avatar

Super8  4 years ago  

Same thing also happen in Corvette L88. Even it stated in 430 Hp, but actual output is 530 @ 6000 rpm. The net is over than 450 Hp @ over than 5000 rpm. 430 Hp is stated to fool insurance company. It somewhat high revving just like RA V because even it using 4.10 final, the car still can reach 140 mph. The automatic 3 speed with 3.36 ratio can reach 159 mph + and maybe with 4 speed 3.08 final, it can reach 180 mph.


User avatar

Super8  4 years ago  

@ Bijan: 371 Hp? That's cool! I remember when my father asking about his friend RA V GTO in USA. He said all of the RA V engine is never underrated to 425 Hp. True output is 525 Hp @ 7500 for GTO and 475 Hp @ 7300 for Firebird. Those 2 got a 455 Hp net @ 7000 rpm when my father's friend dyno it in a tune shop. Pretty good huh? All of those part is not readily available from Pontiac and must ready to wait a little longer than expected.


User avatar

Bijan  4 years ago  

@ Super8 : The 1973 Trans am SD 455 is faster than 1969-70 RA IV , maybe close to the Race breed Mechanical lifter RA V ...
I want to say , this car , in the first , is a street car , no semi race cars that came from GM , Chrysler , AMC and Ford in 60' . or a one off dealer made cars !!!!!
1973 SD 455 was a GT , ran on 91 octane fuel , and incredibly passed All Federal and state emission and even noise laws , with 8.4 Compression and down rated 310 net Horse Power , and actual tested in 371 plus .


User avatar

Bijan  4 years ago  

The 1974 SD 455, maybe close to the 1970 RA IV , so the 1974 SD 455 came with a milder Cam and 290 SAE net horse power , some stuffs between these two engines are the same , The Heads and the Camshaft and ... and the 74 sd455 came with 8.4 compression , but the RAIV came with 10.8 .


User avatar

Super8  4 years ago  

I guess you can compare it with RA IV engine. It might be had almost identical stats just like this one or maybe 455 SD is faster than RA IV


User avatar

Viking  4 years ago  

The Mustang went down in performance rather quickly in the 1970s. In 1972 the Mach 1 with 351 Cleveland engine had a very respectable 266 hp at 5600 rpm, by 1973 it was down to 248 hp. In 1974 it was replaced by the Pinto based Mustang II with a V6 (with the 302 cu. in. V8 available in subsequent years). Ford's 302 V8 had no more than 139 - 143 hp during the '70s. Pontiac had no real competition for the Trans-Am in the bleak years to follow. I learned to drive in the mid-70s with a 1972 Mercury Comet GT with 302 V8, and a whopping 143 hp, 242 lb/ft of torque.