customblackbird

iTrader: (15)

Hey guys its been a while since ive posted on the forum but I got the firebird to the track this fall with the 521 BBF and had some issues... alot was traction

just a recap, rear is a ford 8.8 and is about 1.5" wider than a stock 9bolt on each side, so 3" wider total. Im currently running 17x10.5 rims, 6.8" backspacing with a 315 tire (26" tall) with basically no mods to the wheel tubs. The rear springs have been cut about 1 1/2- 1 3/4 coils. but this new stuff looks like i might need to do some mods.

To help with my loss of traction at the strip Im going with M/T ET streets and new rims for the rear that i can swap out on race day. I purchased a set of summit 15x10" rims http://www.summitracing.com/parts/SUM-521-5166PS25/ and they have 6.5" backspacing, a test fit put the rims outer face/edge right in line with the outer edge of the rear quarter. so it looks ok.

The ET streets are 295/65/r15 tires that are 30" tall (i know its alot but I wanted to lower my trap speed RPMs. http://www.summitracing.com/parts/MTT-3762R/ they have a 11.9" section width and 10.9" tread width. And measuring from the ground to the wheel well lip puts me at 29.5" till where the tire will contact the quarter. At 30" its right at where the flat section meets the curve going up the rear quarter.

Does anyone know if a 295/65r15 drag radial will fit a stock 3rd gen wheel well? Since ive cut 1 1/2- 1 3/4 coils off the rear coils Im sure its too low for this setup and ill have to swap in a new set of springs. The thing is that I dont want to mount the tires to the rim bc then I own the tires and cant return them.

watajob

iTrader: (29)

I'm thinkin' a set of not WS6/F41 stock springs, (higher ride height) and even some air shocks/bags will be needed. Also, an 8" wheel may be enough as I know a 295/50 will go on it. A 65 aspect ratio, being more sidewall, should also be able to.

customblackbird

iTrader: (15)

As far as i kno the stock rear springs of all cars including the V6 is the moog 5665s. Thats what i have and thats what i cut 1 1/2- 1 3/4 coils off to achieve the ride height that i have. I cut enough off where the springs fall out before the rear is fully lowered.

If your talking about another spring can you post the part #?

The stock springs moog 5665 have a 105lbin rate and are linear. And when installed in the car at original height (new springs) the rear wheel gap is quite large. I wish i had my stock rubber spacers to put back in... ugh. The rims and tires are bought and i have them in had... however im restraining to mount one bc then i cant return it.

The 295/65 r15 tire is 30" tall... which If i knew actually how big it was i would have went with a 28" tall tire.