Thread: The monster....600 HP EFI 1974 Trans Am

Ok ive got build threads on 2 of our 3 current pontiacs and I have saved the best for last. This is our 1974 Trans Am, we bought it off of eBay in 2008 as a "fully restored" driver and when we got it home from AR we realized it was anything but. It became more and more obvious that the car was hacked and pieced together by a body shop owner with the full intention of trying to turn it for a profit. The "rebuilt" pontiac 400 was re-ringed with all stock components. It was weak at best and began to lose oil pressure after 2 summers of cruising. The brand new Year One restoration body pieces like the front air dam and wheel flares were sheetmetal screwed to the car. Many aspects of the car were not up to our standards to say the least.












The first thing on the agenda when we got the car home was to replace the rubber fuel lines that were TOUCHING the headers, the patched together kinked and rubber hose transmission line and the rusty original brake lines with Inline Tube replacement pieces and professional bent one piece tubes by me














Next we dropped out the rusty original gas tank and installed a brand new one






The rear end contained an original wore out posi with 2.56 gears. The axles were destroyed where the bearings ride on them too. We put a brand new Eaton posi in, new 30 spline axles and a 3.42 gear set.



The lock pin in the diff was also sheered off














At this time we also installed Alston subframe connectors and solid body mounts







The car was parked from around 2010 until this winter because we no longer trusted the engine to drive the car.
The next segment of the build is the assembly and dyno tuning of our Alum. head EFI 462, race prepped TH400, and finally dragging the car into the shop and tearing into it which brings us up to date to where we are currently at with the build. The idea of the build is ANTI-drag car. It is getting 1LE dual piston front brakes, rear disc conversion and 275 tires all the way around. We are building it to just be a monster street car with 0 ****s given about extra tenths at the track.

Awwwwwesome wheels! Love the look.

lol, they did look cool but the wheels were bolted on with adapter spacers, that is how they ended up on the GTP instead and we are getting different wheels for this car once its done. We werent going to try to put 600 hp down through adapters

Yea. Probably a good idea. If you like the style of wheel enough you could probably get some American Racing Torq Thrusts. I think that they make them in the correct bolt pattern for that car. I could be wrong though.

Heres the rest of the story up to current

After the car was parked we knew the engine was no good even though it still ran so we started collecting parts and building a 462, Half filled hard block, steel crank, forged rods, KRE/SD performance aluminum heads, roller cam.




Then we decided it absolutely had to be fuel injected but all the EZEFI kits and crap like it suck. Plus we already have MEFI burn for tuning boats with MEFI controllers. So we took the GM MEFI4 harness and controller kit for a ZZ502 crate motor. Modified the harness so the wires were all in the right places, gathered up an intake with injector bosses, fuel rails regulator, Scorpion 1000CFM throttle body with progressive linkage, then I took the distributor for a 1981 turbo 301 pontiac because it was the only pontiac style distributor that had a electronic reluctor in it. Cut the back of the cap out and mounted and wired in a ICM for a standard GM ignition. This is how it all turned out






video of one of the first fire ups

Rough rigging on the dyno just to get it fired up again


Dyno video
https://www.youtube.com/watch?v=G8HzNekaBO8



Final numbers were somewhere around 595hp on E85 and 575hp on 93 octane. We spent TWO WEEKS on the dyno total, essentially writing the tune from scratch the first week only to find that the base file we started with wouldnt rev over 5750 no matter what we did to it. Ended up taking a tune file for our boat motor and transferring all the tables over to it for the 462.



Fan and radiator combo that we just ordered for it




Full built TH400 for it too


So we pulled the car out of storage this fall when the shop was slow and tore into it.

First thing we did was pulled the rear cover back off and put a TA performance girdle cover and ARP cap studs in it to try and let the 10 bolt live.




Then I tore the trans out, wont be needing that POS anymore anyways


This is the before shot, worn out, tired 400. We tried to jump start it to drive the car up from out back and it popped and locked up. Good timing


After shot


Tore into it to see what broke and if we could piece it back together and sell it to recoup some $$$


Balancer snout broke off and ran through the timing chain


Ripping the rest of the AC crap out for the delete panel

Firewall cleaned up for delete panel

delete panel installed

Test fitting the Alston firewall braces


And that brings it up to date, thats as far as we made it before we got swamped for the rest of the winter. Hopefully we can get the EFI motor dropped in and wired up ASAP and have her back out on the road this summer finally!

i like old meets new. engine sounds like a beast.

your a mad scientist aint ya lol

My approval................................you have it.

Originally Posted by Scottydoggs

i like old meets new. engine sounds like a beast.

your a mad scientist aint ya lol

EFI was a must. I wish the quadrajet that came off of it was flammable so I could KILL IT WITH FIRE. It really was a evil POS. I put around 8k miles on the car before we parked it and I raced a GTP similar to mine one night. This was before I ever owned a L67 or anything. That mother****ing Qjet coughed and sputtered and he pulled me so hard you couldnt tell we were trying to race. Never again!

heres a video of the carb laying over on its face and me getting pulled by a 2007 Eclipse GT

ive had my share of failed quadra bogs in the past, when they go bad, boy do they go bad.

The car had a Edlebrock performer on it when we bought it and that was absolutely terrible, it would barely start or run. We bought a restored/resealed/re-plated Qjet from some place. It would run great about 30% of the time, take off burning rubber sideways. As soon as I tried to race someone it would bog and cough and sputter. We tweaked and tuned that thing for hours one night until it was perfect to take it to the dragstrip the next day. Drove there burning rubber around corners doing pulls to 140 ran great. As soon as I pulled out onto the track it was totally ****ed and wouldnt move out of its own way, ran like a 15.90 @ 86mph I think. Wasted $30 to get in and $60 on gas to drive there and back ran like **** all day. Pulled out on the road on the way home POS took off burning rubber sideways.

sweet t/a me and my buddy are building a TTA we found a wrecked 89 TTA and are swapping everything over into a 87

Originally Posted by Anthony Smith

The car had a Edlebrock performer on it when we bought it and that was absolutely terrible, it would barely start or run. We bought a restored/resealed/re-plated Qjet from some place. It would run great about 30% of the time, take off burning rubber sideways. As soon as I tried to race someone it would bog and cough and sputter. We tweaked and tuned that thing for hours one night until it was perfect to take it to the dragstrip the next day. Drove there burning rubber around corners doing pulls to 140 ran great. As soon as I pulled out onto the track it was totally ****ed and wouldnt move out of its own way, ran like a 15.90 @ 86mph I think. Wasted $30 to get in and $60 on gas to drive there and back ran like **** all day. Pulled out on the road on the way home POS took off burning rubber sideways.

clearly you had that f 'er Murphy riding shot gun lol

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