I run 10's with 5.75" b/s Jim and it's about perfect for my application,6" would have had me rubbing on the inside.

If you are going with the Nitrous I's, then they are custom built, and you can pick backspace.

In that case, on an 18x8 and 20x10 set, I would suggest a 8" with a 5" backspace and up to a 255 wide tire up front.

Note: For a stock suspension, I would run a 9 with a 275, and more backspace, but for an AirRide set up, and for the sake of being safe, I would suggest the 8" with a 5".

For the rear, a 10" wheel with a 5.75, and my suggestion... go with a 275/40/20. This is wide enough to look good. Will give you all the clearance in the world for when you drop that sucker on AirRide.

Note: For a stock, or slightly lowered car, I've done as wide as a 305 wide tire on a 10", but again, to be safe, and to set you up with a wheel and tire combo that will definitely work before and after your suspension mods, I would suggest the 275/40/20.

Fyi: the Nitto NT05 comes in both sizes you need.

Hope some of this helps.... :cheers: :lateral:

Here is what a 275/40/20 looks like on a 20x10. This car was not lowered at all.
The 275/35/20 is what we put on the back of Johnny's black Tempest.

Hope these photos help>

http://i37.photobucket.com/albums/e9...970_gto_05.jpg

http://i37.photobucket.com/albums/e9...kedinbooth.jpg

I am running Foose Nitrous IIs on my 66 GTO.

https://lateral-g.net/forums/showthread.php4?t=16289

They are 18x8s with 225/35/r18 BFG KDW (front) and 20x10s with 265/30/R20 BFG KDW (rear). They are a custom backspace front and rear. Even at the lowered ride height, they still have not rubbed. the rears have about 3/8" of space on either side of the sidewall and sit up inside the fenderwell. the fronts can turn lock to lock and not hit anything, but only the tire sidewall is inside the fenderwell. we bought one of those Wheel-Rite measuring tools and ordered the wheels based on those measurements. i would highly recommend using this tool.