455 SUPER DUTY Trans Am vs 455 HO GTO

The 455 HO GTO is a 4 Speed manual and the 455 SD Trans Am is equipped with GM’s Turbo 400 automatic transmission. According to the guys of Road Test T.V. Now after watching the video and if you listen to the GTO it sounds a little more healthier than normal.

To be Honest the 1972 GTO 455 HO was only rated at 300 Horsepower with the new net ratings which was supposedly the true power of the motor with all the accessories attached and going through the transmission. The previous years all the motors had a gross Horsepower which was a lot higher. But also they had higher compression ratios as well, which made more power.

I remember as a kid in the 70s the Trans Ams always beat the Heavier GTOs, by the early 70s the GTOs gained weight and combine that with less power they were not what they used to be. But I am a die-hard Pontiac guy so I love those ’68 to ’72 GTOs I can care less really.

Before I go any farther I like to thank the guys over at Road Test T.V. on You Tube they have some awesome videos and well here are some links so you can show them some love.

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The 1974 Pontiac Trans Am 455 Super Duty is a rare car only 943 were built 290 Net horsepower and 395 lb-ft of torque from 1973 to 1974. The original rating of 310 HP  though that rating was based on the emissions non-compliant “pre-production” engines, That rating appeared in published 1973 model year Pontiac Ads and Articles, which had been printed prior to the “pre-production” engines “barely passing” emissions testing.

A production line stock SD455 produced 253 rear wheel HP on a chassis dyno, as reported by High-Performance Pontiac magazine (January 2007). This also goes with the 290 SAE net horsepower factory rating (from the crank). Skip McCully verified that there were no production SD455s released to the public that were fitted with the 480737 cam. And a very low 7.9: to 1 compression.

There were a few road tests of the SD 455 Trans Am back in the day ranging from 13.9 to 14.2

A Stock 1972 GTO 455 HO 4 Speed according to Motor Trend was 15.4 @ 92 mph for 1/4 mile and 7.1 sec for 0-60 mph with 4 Speed 3.55 Gears. A few other sources have it at mid to high 14s

Or you could ask and 1972 GTO owner that will tell you they never lost a race with theirs even beating Hemis. Now I am a Pontiac guy but I also that the Street Hemi was a wild beast even in 1971 so hey who knows right.

Now Both cars are competing in the Pure Stock Drags, the modifications are limited to porting, blueprinting, and minor weight reduction without altering the stock appearance. That means stock intake manifold, stock exhaust manifolds, and street tires.

But a lot of these guys are true mechanics or knows someone that knows the ins and outs of building a motor pushing out way more power than stock. I do believe that a 0.30 inch overbore is allowed as well do not hold me to it but I can’t see that not being allowed due to the fact many of these motors would have to be rebuilt and you have to bore it for the rebuild even if its back to stock specs.

Now I am not going to spoil the outcome of the race but I will tell you, that both cars are a tad faster than stock. And it was a very interesting race for sure and I hope you enjoy it.