Pontiac Firebird Trans Am 455 Super Duty specs

When a stock SD from the factory with just a tune open headers and slicks and gears you got a 12-second car.
Haters will hate.
Even detuned this was a true muscle car monster.
There slept one by the government if you look at the horsepower rating it's at 4000 RPMs most of you are smart enough to figure that one out

Car & Driver in 1973 tested the SD 455 Firebird at a 1/4 mile speed of 13.751 seconds at a terminal speed of 103.56 mph. That is 'fast' for classic car period.

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Delete the ¼mile time, it was accomplished on a prepped dragstrip with rollout

That's right.

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

tran sam are cool

True classic...

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

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

@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.

@ 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 .

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.

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

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.

@ 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.

@ 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 .

@ 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 .

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.

@ 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.

@ 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 .

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 .

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

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.

@Bijan I completely agree. The SuperDuty was the fastest car built in the U.S. between 1973 and 1989. No question about it. Performance was in decline starting with the lowering of compression ratios, and the installation of early smog equipment around 1971. It was amazing when out of nowhere this super duty engine came in 1973. A full 310 net horsepower is quite a bit more than most of the 400 plus gross rated engines from the late sixties. Even the monster 425 hp (gross) 1971 LS6 454 engine was really only 325 hp net. Two years later in 1973 the only Chevy 454 was the LS4 with 275 hp net. If I remember correctly.

All told, 1973 was a very good Trans Am year. You had the best production engine, the best styled, and the best sales to date. Perhaps it was because Trans Am was now the only game in town. Cuda's and Challenger's were cut down to mere a 240 horsepower 360 V8 as their weapon. Mustang, got big, heavy, and sluggish, with the 4-barrel 248-hp 351 engine as the top offering. As for T/A's little sister, the Z28, the 245hp detuned Corvette 350 V8 was as good as it got, and also the 275 hp LS-4 Corvette .

The 1973 T/A proved that when the engineers run the asylum, excellence and creativity can prevail. But in the early seventies, performance was a bad word, and tough time were ahead for the mighty bird.

@ Wiking : You are always according to the car and driver ... All right
Car and Driver say in May 1973 that : Just leave the shifter in D, and the Pontiac Trans am sd455 rush down the strip run after run with sub 14 ETs .... without even breathing hard in the process , in 5400 rpm shift point !!!!!!! and 3850 lbs car .
Me and some of my friends in Europe take 12.8 to 13.1 with 100% original street ones with 4 speed and 3.42 . with shift point between 5700 to 6000 rpm .
Several times 166 to 171 from my friends with 3.42 and 7050 rpm to 7300 rpm for 1973 of course , not 1974 with 301-313 that revs down something about 500 rpm .
. It wasn't until the advent of the $60,000 Corvette ZR1 seventeen years later that a domestic car could realize those numbers.
Sorry about my English .

The name Super Duty brings back memories of the famed lightweight Catalina drag cars of the early sixties. Armed with beefy horsepower producing engine internals and lightweight aluminum body parts, the Super Duty's were race cars with lights and license tags. When Pontiac decided to turn loose a modern version of a race car motor for the street, tagging the engine with the Super Duty moniker was a natural. As smog motors go, until the advent of the wonderful computer controlled engines we enjoy today, this was one of the most powerful engines produced. Sure Chevrolet put L88's & ZL1's in Corvettes, Chrysler did some "Street Hemi's" and Ford built the 427 side oiler and OHC 429's; but these engines were spawned in a different era. The concept of "Win on Sunday and Sell on Monday" was all but dead. Pontiac engineers kept the faith. The Super Duty was an engine that for all intents and purposes, should never had seen the light of day, but on March 15, 1973, permission was given to release the engine into production cars. The purpose built cylinder heads, engine block, wildly aggressive camshaft profile, and power figures of 310 net horsepower at 4000 rpm and 395 lb/ft of torque at 3600 rpm certainly did not fit the moods of the times.

@ Super8 : you better type the 1973 Pontiac Firebird Trans Am sd455 3.08 Automatic .
Some 70 % of the classics of this site add with incorrect performance data , specially Top speeds from the 60' Ferraris and Maseratis to the American Muscle cars and the ponies . ( all AC's ) .
This is Fastest U.S car between 1973 to 1989 , thats it . with top speeds of 171 to 177 from manual 3.42 to the Auto 3.08 .

@Super8 a very nice car to add. It was the fastest car of 1973 despite the low 8.4 to 1 compression ratio. I believe all your stats are correct. I have only two tests for the car. Hot Rod magazine got 0-60 mph in 7.3 seconds, and the quarter mile in 13.54 at 104.29 mph. Car and Driver tested one and got a quarter mile of 13.75 at 103.56 mph. Very impressive for 1973.