Now my car has 15x7 with 215/70/15 fronts and 15x8 with 275/60/15 on the rears with 2" lowered all the way around.

Tire and wheel sizes
 

I am currently running 15x8 corvette ralley wheels with 245-60x15 bfgs on the front, and 275-60x15 bfgs on the rear. Cae is set up with 2" drop all the way around. Currently no rubbing or other fitment issues.

15x5 fronts with 215/65 high speed tires

and 15x8x5.5bs rears was 275/60 MT Drag radials [8.9"tread footprint]
now 295/55 drag radials [needed 5/16" spacer] to shoehorn in there...
11"tread with 28"diameter :)

convss. I have 15X8 rear and 15X7 front, but I am wanting to get 15X8 for front so they are all same size. the car came this way when I bought it. it has 245 60 rears now. question. is backspacing on these 4.25 or 4.50?

either bs should work for you
do you have stock 15x8 rims now?
do you want the bs to match on the rims you want to purchase:confused:
that way you would have 4same size tires on 4same type rimsBowtie smiley

the rear has 15X8 rallys. yes, I want the same size all the way around. the seller said the rims were GM rallys. I don't know the back spacing on the rears. but I hear either 4.25 or 4.5. I am looking at VISION AMERICAN MUSCLE 55 Rally Series silver wheels from Summit racing. these are 15/8 with 4.25 backspacking.

I have 18x9.5 rear with 285 40 18 nito
Front is 17x8 with 245 45 17

I run 15x7 Torque Thrust wheels with Nitto tires in 225/70 size for the front and 275/60 on the rear.

Factory 15 x 7 Rally wheels with 4.25 back space.. Tires are 225/70r15 Cooper..

Here is my 69 with Wheel Vintiques 15 x 7 4.25 back space Series 64 Chrome Reverse.. Nice wheels, that rode smoothly..