Help me plan my race car project
 

This is possibly my first real post in the Race section. :3gears:


I’m a few years away from being able to retire, and I want to build a dedicated drag car and get into bracket racing. Looking back at my GTO project, I realize that I wasted a lot of $$ by changing directions multiple times, so for this project I want to develop a solid plan before I start and then stick to it. Once I have a good strategy, I will begin collecting parts as money allows and start the build when I am ready.
There isn’t really a specific budget, but I want to keep costs reasonable as I will only be able to do 4-5 races a summer due to the few events/tracks up where I live (all are 1/8 mile). I already have a stash of parts to use as a starting point, and want to plan the build around them to keep costs down. Being a bracket car, I’m looking for a strong, reliable and consistent setup.

What I have to work with so far:

-79 Trans Am rolling chassis with 10 bolt rear (assume I will use 28” slicks or drag radials)
-factory 2 bolt 481988 block
-“as cast" round port Speedmaster 72cc heads
-forged 3” main, 4.250” crank
-forged 6.800” I-Beam rods
-factory 1970 dual plane intake (planning to do the Cliff/SD mods to it)
-800CFM Q-jet
-Turbo 400 transmission that I will rebuild with appropriate parts & shift kit

Assuming 91 octane/10% ethanol for fuel, I am looking for input on:

-recommended camshaft type & specs that complement the heads/intake/carb I will be using (note: I have no plans to port the SM heads and will run them as delivered other than swapping springs as required.) The heads are reported to flow 289/202CFM at .600 lift and I want a cam that will fully use the airflow capability with either 1.5 or 1.65 rockers. I'm OK with solid lifters if that saves some $$. If a flat tappet cam will get me where I need to be that is great; a roller cam is also not out of the question if needed.
-recommended target compression for the cam/engine/fuel combo
-recommended size of round port headers to match the combo (I see Doug’s has 2 sizes for round ports to fit in 2nd gen F bodies)
-recommend rear gear ratio
-recommended stall speed for converter
-I plan to install main studs. Are 4 bolt splayed caps needed at this level?
-block fill required or recommended?

-anything else I should know? J

I appreciate that most of you have spent years to get your combo’s dialed in, and any advice to get me on the right track is appreciated. Bear with me as I ask a lot of dumb questions along the way. Pontiac powered race cars are few and far between up here so hoping to represent the tribe :canada2:

If your 10-bolt is stock, the first thing I'd do is get a consultation going with Strange or Moser about upgrading. Stock axles won't survive with slicks. The conversation will be upgrading your 10-bolt vs switching to something else. Include your driveshaft and u-joints in that conversation. Sounds like you have the benefit of time to ponder alternatives.

Give lots of attention to bulletproof reliability so you'll have more fun and less frustration.

Eric

Hi Eric,

Thanks for responding. My initial plan was to upgrade the 8.5" 10 bolt with better axles, welded tubes, C-clip eliminators, a support cover, and a spool. Driveshaft would be an upgraded unit with 1350 joints and matching yokes on the trans/differential. Having zero racing experience, I am not sure if this is a reasonable plan or not.

You might want to look at a TrueTrac over the spool. It will make everything easier and should be plenty strong for your power level and weight. I'd also investigate using the 30 spline version (28 stock) and take advantage of the bigger axles just Incase you up the power level down the road.

IMO a Nitrided SFT camshaft with quality lifters is the best option for reliability for a dual purpose vehicle.

Thanks Paul. I had planned on 30 spline axles anyway so will look into the TrueTrac.

Built the short block strong and with light internals so it works best for you money input and with it being built strong you up the motors power level safely with better top end parts and not loose sleep at night.

1) use hard block to make a fill up to the bottom of the water pump passages.
Believe it or not even a street motor will run a minimum of 10 degrees cooler by doing this and the bottom of your cylinder bores will not get chewed up especially if you run crank strokes longer then 4.00”.

2) run longer Aluminum rods ( greater then 6.625” along with the needed pistons ) to maximize internal weight reduction.

Why is this a big deal you might ask.
The reason is that every pound of rotational weight reduction increases vehicle performance a minimum of 4 to up to 10 times more than that same amount of weight reduction done any where else on the car.

You will be stunned at how much faster the motor buzzes up and that faster rpm gain translates directly into the vehicle accelerating faster.

Hi Steve,

Thanks for the suggestion on block fill. For the rods, I already have a set of 6.8" steel rods that I will be using.

Your plan sounds reasonable.
I'm using a TrueTrac differential in my road race car based on recommendations from other road racers. No track time yet to report on. I can imagine it might be easier to drive on a drag strip with inconsistent prep?? If a car with a spool has sticky track under one tire and less traction on the other side, it definitely will try to steer the car.

FWIW,
Eric

Great info. The closest "track" is actually an air strip that gets closed down 2 weekends a summer and turned into an eighth mile strip. Consistent traction is one of my concerns so this is a good consideration.

Hop stop bars are an easy to install traction aid for a coil spring rear car.

Keep the rear sway bar on also since that helps .

Buy a race car that’s already built and proven from someone who’s retiring from racing.

For 25 to 50k you can buy a 100 to 200k car and start racing next week.

But what’s the fun in that? ;)

I would build the rear end/ rear suspension/trans and driveshaft ready for 10.00 and then use what you have for a motor with a big SFT cam/lifters. Then later when you have more money you can upgrade your motor to go faster. My rear is a 1972 10-bolt with a Strange spool, Strange billet bearing caps, Ford ends welded on, tubes welded to center, Moser 33 spline axles and an aluminum cover with bearing cap preloads. I use Caltracs with split mono leafs but was using stock leaf springs and cheap traction bars down to 10.4. With the motor parts you have you should be able to get down to 11.00 or slightly faster with the right converter. You should put a rollbar in right away. It's always an evolutionary process unless like Bman said you can buy a ready to race car for 30K and go low tens to high nines right away and save money in the end.

LOL, that goes against everything I believe in...building things IS the fun part! :) Winters are long, I need something to keep me busy!!

The need for a rollbar was something I was wondering about. If I can build the car to get into the 11's in the 1/4 that would be awesome. I believe I would need a roll bar if quicker than 11.50 in the 1/4, but not aware of what the equivalent requirement is for the 1/8th. I will consider one regardless as I think it could help stiffen up the chassis.

^^^^^^^

This

Sounds great on paper but I'm unlikely to squirrel away 25K without the wife finding out, and Chevy power is most common up here and not my style. :)

I already have the car and 30% of the hard parts so really wanting to move in that direction. Growing the parts stash one pay at a time is more likely to get approval (forgiveness).

So camshafts....since no one has recommended one, maybe I should start with what I was thinking and get some feedback from there.

With a 4.155" bore and 4.250" stroke I come up with 461 cubic inches, practically the same as the 463 in my GTO. I have the 230/236 Stump Puller in that motor with 1.65 rockers, ram air manifolds and 3" exhaust, 800 Qjet and a factory intake modified by SD. It pulls like crazy...so something similar or a step up seems like a place to start for a fun bracket motor.

Considering this will be a track car, idle & vaccum are not as big a concern. The SM heads appear to have about a 70% intake to exhaust ratio at .5 to .6 lift so thinking a dual pattern cam still needed. With a Qjet and modified intake + headers, is a 246/253 cam on the small side or about right? I believe compression should be somewhere around 10.5-1 for 91 octane. This is similar duration to SDs Road Paver cams and see several members using them in 455-463 street cars with 6X heads and better. I'm not scared of slightly more cam if it is a logical thing to do. I realize the intake is a limiting factor but it is a place to start.

Thanks

Tell wifey it’ll be cheaper in the long run and that you’re selling all your stuff and that Firebird to get a better car.

She’ll come around.

Asking for forgiveness is always easier than asking for permission. :)

On this we definitely agree!

If your only planning on 11's for ET, should be really easy.
But usually the bug to go quicker and faster comes quickly.

Also, havew to decide if you want it still streetable, or towing it to the track.
Towing it it can be made very fast easier.

Roller cam for sure either way, solid probably better. (just my 2cents)
With the TA, the leafspring setup is easy to work for 10/11 second times.
Faster than that ladder bar or 4 link would be better for strength and adjustability.
Narrowing the rear and tubbing then comes into play.
Then more money.


:D