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1973 Pontiac Trans Am 455, Garrett 77mm turbo (now 88mm!) & Methanol injected

original build courtesy of Mark L...1064 hp (keep watching, 1200hp soon!) before adding the Meth injection. Proud new owner Aron HK

The day I finally got it through DE inspection, Aug 2010.

polished heads and intake sitting on freshly machined block. Hopefully shortblock will start going together in a few days.

Glass front end being prepped....almost done.

Major changes for fall 2011 (hopefully all will be done as I want some street time this yr!)

*tilt one piece front end installed

*House of Kolors Galaxy Grey paint!

*compression lowered to 8.25:1 with dished Arias pistons

*switch from 1.5 to 1.72 HS roller rockers changes net lift from .520 to .590

*upgrade to 88mm Garrett GT4718/4788 turbo from old 77mm Garrett

*polished Northwind intake and polished ported Edelbrock aluminum heads flowing 320 cfm @ .600

Engine block smoothed of casting flash in prep for build and paint. House of Kolors Galaxy Grey should offset the polished parts well on block, valley pan and timing cover.

The new polished Northwind intake. Polished ported aluminum heads to follow. New Garrett GT4788/4718 88mm turbo. So many changes....I'll start making some posts with pics here soon. Expecting around 1200 hp at 15 psi.

TA on its way to the enclosed car carrier owned by Frank of to start its journey to DE from AZ after the Pontiac Heaven event, April 2010


Since the 73 Trans Am came to me in April it has begun its slow transformation from a Drag Racing car as Mark had it, to a street car in the Pro-Touring style with eventual part time duty as a road racer. This is what I have done or is in the works....and its gonna be it for now cause I have no more cash to play with for the

-3.08 rear with S10 disc brakes. Had 3.73s, but turbos like LOAD, so the taller gears will be better.

-Converter restalled from 4600 to 3000....tight. Again, turbos like load

-methanol injection system with boost switch at 40%

-Oil accumulator to back up oiling system under hard right turns

-moved wastegate to clear front R tire

-consolidated and cleaned up wiring

-March Performance Style Track Serpentine System

-Vintage Air heat/air/defrost

-1987 WS6 steering gearbox 2.5:1

-new burnt orange cut pile carpet w/insulation

-RSX leather race seats

-new door sills

-Kenwood stereo & speakers

-new door hinge pins

-12 volt fan added to turbo oil cooler

-radiator dropped/tilted forward with intercooler

-glasstek early style tall TA hood scoop with piping reroute to put stock hood back on

-Complete fiberglass front end purchased. Will tilt forward. Not going on for a while...when the body gets reworked and repainted

Again, its not all installed yet because I hate taking it off the road! LOL.

Thanks! Aron HK

Turbo system installed in 2008


The first run @ 10 psi = 788 HP and 744 ft-lbs of torque at the rear wheels.

The next 2 pulls were 12 psi = 789.7 HP and 827.9 ft-lbs.

The last run was 15 psi = 889 HP and 822.3 ft-lbs of torque at the rear wheels.

The drivetrain loss is 20%, so that converts to 1064 HP and 987 foot-pounds of torque at the motor at 15 psi.

I built the turbo system completely by myself with a real welder finish-welding the parts. There is a video in the links here to a webpage showing the dyno run. Its the last car in the video. Their numbers flashed on the screen were incorrect....correct ones are listed above.

The Trans Am as I found it (Mark L).

BY MARK L: This is a 73 TA I found in a machine shed. It actually belonged to a friend and I didnt know that he owned it. It is an original show car that he bought and started using for everyday transportation. It started to surface rust on the hood underside and a judge at a car show somewhere asked him to not put the car in judging. It was fine for him to bring it to the show but they could not judge it due to the surface rust. So he put it in the machine shed at a friends house and totally dismantled the car.

When he offered it to me he had completely taken out the motor, drive train, rear end, and dropped the front frame stub out the bottom. Because the spoilers and flairs were all moulded in and painted he could not dismantle the sheet metal so that is how I found it. Sitting on make shift saw horses like a model car body, completely intact with no frame and or running gear.

Once I started to reconstruct it I had to build it all back together with the sheet metal all installed. The pics you see at the top are the first days on the street. First car show in 2002. While it was apart I built the motor (see below for specs).

Video and audio clips

Specs as of 2002
Block:Original but Service Replacement 455 (now 462 cid)
Pistons:Forged TRW SD single trough
Rods:Fully floated, blueprinted, polished, and ARP'd cast rods
Heads:Fully ported 6X-8
Cut and chamber ported to 97cc
Comp ratio:9.1 : 1
Cam:Solid Crower 264/268 degrees @ .050
.552/.558 net lift 108 C/L
Lifters:Cool face solid lifters
Headers:Headman 1-3/4 inch
Intake:Edelbrock Torker II
Carburator:830 Holley
Rear end:10.5" 10 bolt, 3.73
1/4 mile ET:12.0 sec @ 110 MPH
Mods in 2003
Power adder:Cheater nitrous plate system
1/4 mile ET:10.9 sec @ 121 MPH
Mods in 2006
Intake:Wenzler tunnel ram
Carburation:Twin 600 DPs
Twin plates to use the cheater nitrous thru
Water pump:Meziere electric
Other:Removed the heater system
Power steering replaced with an S10 manual gearbox
1/4 mile ET:10.25 @ 133.8 with a 200 shot nitrous (Oct '07)
Mods in 2008
Power adder:77mm turbo w/.96 A/R turbine
5 inch exhaust exit, 4 inch electric dump valve that will
open on request and exit out thru the front passenger
fender. When closed it exits back under the car and out the back.
From the turbo the charge goes thru an air to water
intercooler before going back up to the blow-thru 830 Holley.
Rather docile on the street and with the electric exhaust valv
should sound wild at the drive-in.
Cam:Boost-compatable 248/248 @.050 .520/.520 net solid with a 114 LCL
1/4 mile ET:Should be easily in the 9s.


Turbo installation on 73 TA
Night at the track , my TA with previous owner Mark L
73 TA turbo 462 Videos
More Cars of the 1970s
More Pontiac Coverage

1722 car nuts gave this a thumbs-up. Do you? Thumbs-up


Anonymous on May 21, 2008 said:

very nice

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raspantienator on Aug 19, 2008 said:

Nice-I had a 74 455 but I prefer your style bumper to the 74's

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snakepitt1 on Aug 11, 2009 said:

Pontiac power is alive and well!!!!

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Anonymous on Sep 11, 2009 said:

sweet ride ,good luck

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Anonymous on Sep 15, 2009 said:

Thanks for sharing this with me, Mark! You always were my auto expert.

~ Al Thomas

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Anonymous on Dec 23, 2009 said:

Very nicely done,super rwhp numbers WOW !!! That (if you can get it to hook) will easily make some low 9's runs, tune it a season, you got that 8's ET slip we all so want! Congratulations on finishing the turbo setup, must have been a bit of nerve racking experience to learn about what all you needed to match it all up to each component. If you don't mine could you send me some info on the turbo,"electric dump gate" and what is in the engine now down to the smallest level. I am getting ready to do a "Turbo" on my 66', 421 four bolt main, now a 462ci engine for next year. Please contact me at

Kind Regards, jts

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Anonymous on Dec 28, 2009 said:

thats badass dude

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Anonymous on Jan 16, 2010 said:

Hi, that's a mega nice looking car, well done for getting it going again.

Andy, Wales, UK.

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Anonymous on Feb 25, 2010 said:

car looks good

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Anonymous on Jul 9, 2010 said:

Super !!!! this will be great off and on the track -- bye bye Porsche etc. - Ken .

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aronhk_md on Jul 10, 2010 said:

Thats the


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Anonymous on Aug 17, 2010 said:

I dig the car Aron, and the paint job too! Nice find! Good luck with it, hope you spend more street hours with it than track! Heh-heh!


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aronhk_md on Aug 17, 2010 said:

Thanks! Definitely getting lots of street time. I love just taking it for the occasional errand. Looking forward to adding a 4L80E in the future like yours...will make it even more street friendly and I can see taking it on trips. Good to see you out beyond the PY borders...

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ghpcnm on Jul 10, 2011 said:

All I can say is WOW !!! Nice detailed write up. CONGRATS ON A SWELL RIDE :)

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aronhk_md on Jul 31, 2011 said:

Thanks, appreciate that. More to come in the very near future.....

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Anonymous on Jan 8, 2012 said:


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Anonymous on Jan 20, 2012 said:

Dammit.... I am completely jealous beyond words. People say, "break a leg" if you go on stage, but what do you say to a guy sittin' in this monster? "Break a tie-rod, buddy!"??

If you get this (monster) to hook up at the track and smack 9.1 or lower (shudder), I'll never speak to you again.

I hate really super cool people. :)

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Anonymous on Jul 9, 2012 said:

Hey Aron, What size rim/tire on the back? Stock width rear? Clearance issues? Thanks!

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Warrior on Jun 2, 2015 said:

Congratulations Aron! That is one very wicked Trans Am. It is always a pleasure to hear the stories of incredible cars rescued from barns, sheds, shops, backyards or (God forbid) ultimate destruction.

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Anonymous on Sep 25, 2015 said:

So hows the car today? Still in one piece? Sold it etc....? Just wondering if you have any new updates since the last was 3-4 years ago.

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aronhk_md on Sep 25, 2015 said:

Thanks warrior! Anonymous...she has been in storage over 2 years now, but I am getting ready to go pick her up soon. Hopefully before Xmas. Look for some updates shortly!

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Anonymous on Apr 27, 2019 said:

Big turbo

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