02/03/2019 at #9441David StipekParticipant
Just a note to tell you your engine information regarding 1971 455HO Trans Am is wrong!
1st, the scoop does have a functional Door. It is activated by shoving the gas pedal to the floor, it is 12vdc activated. When switch is made @ throttle stop ( at gas pedal) it powers solenoid in scoop pulling door open.
Next, Engine does have Ram Air IV heads installed! Pulling aluminum 2 peice intake off you will notice the extremely large oval (round) intake ports, so large.. Pushrods they needed to go thru, the intakes had sleeves to allow pushrods to go thru. Only issue here is Pontiac used 3/8″ OD Rods. 7/8″ were available from Pontiac and a direct change out. The difference was a higher Red Line (8,000 rpm) The pushrods are the weak link! Do not use the locking nuts to adjust the lifters! Stock nuts are fine. With the oval port exhaust and Factory tuned port headers (no one made headers you could buy aftermarket) cast steel they did just fine!
Before you reattach intake… Notice it is 2 piece! Under the Carburetor is a cross over plate that does nothing but rob HP and heat-up Carb for faster warmups. In Dayton Ohio, removing this made it a warm area car only! Did not like winters, my wife loved this car and was pissed that I had removed this crossover.
If you choose to replace Cam with hottest from Crane or ISKY, doing nothing more then what I have mentioned you will add 75+ HP… If you switch out Carb for direct Quadra-Jet replacement (850 cfm Holley) you will gain an additional 25-35 HP. IF YOU TAKE TIME… to adjust fuel level in front and rear bowls at 3,500 rpm. You will get max. On dyno the true sleeper was this engine! 335 HP @ 5,892 rpm and with changes… ( Corvette’s beware here!) 438 HP!
My Trans Am was equipt with an on-the column Automatic! Pontiac said they never built Car this way… I took picture’s and Herbie Adams came to my house in Dayton Ohio to verify. It proved out to be the only one! While he was here I had a stall converter and line-lock installed.
Results: With increased (matching the Good years) width rear tires (H/50/15’s) We could melt them with burnouts… Dropping tire pressure to 30#’s we were able to launch 12.58 1/4 mile times (used bleach to get tires sticky…)
Here the fun part… We were on our way to airport an a chance encounter with a Hemi Roadrunner did occur. We exited freeway and went to parking lot of U.D Arena. 3 times (Herbie got pictures) @ launches of 4,000 and 4,500 rpm I pulled 2-3 cars on Roadrunner!!
Using knee, to shift! @ 7,500 and 7,900 rpm I could slide from low, super to drive… Never missing a shift, street tires, factory suspension. Just raising knee, applying slight pressure you could use both hands to grip steering wheel and keeping foot on accelerator brace yourself in seat for torque quenching shifts. Later I installed 5 piece racing seat belt (sent to me from Pontiac…”Free!”)
Finally, your picture or front of TA… Has second generation front spoiler! Original would pull car down to almost 2 1/2″ from road and when entering and exiting driveways danger of tearing it off. It’s original size was 5 1/2″ at each side and center at 6″. At speed you could tear front wheel Dams off if you snaged something.
My TA was white w/blue stripe, same color blue interior. No front console.. But had rear seat console! No air-conditioning…
This was the most underrated Car ever released in 1971! No one has ever given Pontiac credit, Chevrolet certainly did not want the public to have knowledge. Soon after that the performance group at Pontiac was disbanded…
I believe that Deloreon had ideas for the Fiero… Maybe a mid-engined 455 HO? Can you dream of a 455 with tuned port injection or better??? Today??
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