Ridetech for 69 Firebird?

[bret]

My 69 Trans Am clone project is getting to the point where I have to start making decisions on rear end, wheels-tires, suspension, etc. I an finishing up installing a Chris Alliston 6-point roll bar. I already mini tubbed the car this winter. It has an 8.5" rear in it at the moment that will probably be changed out to something that can handle 500+ Pontiac horsepower. I'm thinking about a full ridetech front and rear suspension kit with coil-overs. I will be using a stock front sub frame. Questions are: Do I run a stock width rear if I want 335 tire; are there tire width limitations since the lower control arms bolt up where the stock leafs would on the rear end; what size of tire could I run without adding true-turn, does the narrowed frame rails affect the rear 4-link attachments? Any other input would be great!

On the front:
If you are going to NOT use the Tru Turn system you will be limited to a 245mm tire on an 8" rim with a 4.75" backspace. If you use the complete Tru Turn system [an extra $650] then you can go up to a 275mm tire on a 10" rim with a 5.75 backspace. AND...you'll have much better overall frontend geometry by optimizing the bumpsteer.

On the rear:
There is one corner of the AirBar cradle bracket that must be rounded off because it overhangs the typical minitub by about 1/4". It'll take you about 20 seconds with a grinder. The lower AirBar control arms are offset to the inside by about 3/4" on each side so they will clear a 335mm rear tire. If you are buying/building both a new rearend and new rear wheels then you have lots of latitude of the width of each. BUT you must coordinate those dimensions. Start with the wheels, then get the rearend built to match the offset of the wheels.
OR...if you already have a rearend, then get the wheels built to work with the width of the rearend.
The constant in the equation will be the position of the outer fender lip and the inner wheeltub. Spend lots of time measureing.

[jlwdvm]

I will probably be running Vintage Wheel Works V40's with a sticky street tire, but haven't decided on 17 or 18" wheels. I am wondering if any massaging will have to be done to the front inner fender wells to get a 275 tire in there without too much rubbing.

I am just north of Davenport about 15 miles (Long Grove)...not too far from Moscow!

[bret]

I will probably be running Vintage Wheel Works V40's with a sticky street tire, but haven't decided on 17 or 18" wheels. I am wondering if any massaging will have to be done to the front inner fender wells to get a 275 tire in there without too much rubbing.

I am just north of Davenport about 15 miles (Long Grove)...not too far from Moscow!

If you use the Tru turn, a billet 17" wheel will work. A cast 17" wheel MIGHT work, depending on the exact inner diameter of the hoop. Its close enough that you would have to physically try the wheel on the car. Any 18" wheel will work with the Tru Turn.

Our only direct in-shop experience with fender clearance is with the Camaro..I don't know how much more or less fender clearance a Firebird fender has.
On a Camaro...if you use a 9.5" wheel with a 5.5 backspace and standard height subframe bushings there will be no fender mods neccessary. With a 10" whee; and a 5.75 backspace and 1/2" height subframe bushings [which will lower the ride height by about 1/2"] you'll need to clearance the outer/inner fender slightly for tire clearance. If clearanceing is unacceptable, use the 9.5" wheel with the 5.5 backspace.

[jlwdvm]

Would the V40"s be considered cast or Billet or somewhere in between?

[Buryingthesun]

On the front:
If you are going to NOT use the Tru Turn system you will be limited to a 245mm tire on an 8" rim with a 4.75" backspace.

Im not running Tru Turn system and im running a 255mm on an 8.5" rim with 5" backspace on mt 67'

[bret]

Im not running Tru Turn system and im running a 255mm on an 8.5" rim with 5" backspace on mt 67'

And what modifications did you do to the oem Camaro steering arm to get clearance? Or are you using the Chevelle steering arm? The Chevelle steering arm will give you clearance but unless you modify the rest of teh steering linkage significantly the bumpsteer will be pretty bad.

The other way to get wheel/steering arm clearance with that combo would be to use the oem drum brake spindle with an aftermarket [or custom built] disc brake kit. That combination sits the wheel mount surface outboard by about 1". But that would seem to cause a lot if tire/fender interference unless the ride height is really high.

[Buryingthesun]

And what modifications did you do to the oem Camaro steering arm to get clearance? Or are you using the Chevelle steering arm? The Chevelle steering arm will give you clearance but unless you modify the rest of teh steering linkage significantly the bumpsteer will be pretty bad.

The other way to get wheel/steering arm clearance with that combo would be to use the oem drum brake spindle with an aftermarket [or custom built] disc brake kit. That combination sits the wheel mount surface outboard by about 1". But that would seem to cause a lot if tire/fender interference unless the ride height is really high.

Im have OEM Firebird steering arms.

Im glad you posted about the aftermarket brakes. I think I might have an issue once I swap over from my factory drums to the Wilwood's I just ordered

[jlwdvm]

I notched all of the bars myself with a template I printed off the internet. I used my angle grinder to get the tubes to my liking and mig welded them in. I sprayed the main hoop and rear tubes with SPI epoxy black primer prior to installing to make final paint coverage easier.