68 coupe and convert suspension

[Gmac454]

i am looking to go 17 or 18 inch wheels on my 68 coupe and my convert. they are stock small block cars, with the exception of disc brakes on the front and multi-leaf rear's. what is the best way to find out what tires and rims will clear the fenders and frame with out buying up front and then finding that you are hosed. I am planning on re-doing the suspension like jer67convert but the thought of spending a ton of dough to find out i dropped the front end too much for the rims to fit isn't a happy thought.
thanks

[XcYZ]

17 or 18x8 with 4.75" of BS and a 245/40 in the front and a 17 or 18x9.5 with 5.5" of BS and a 275/40 in the rear will work great.

[BC69]

Just to add to what Scott said, the backspacing is key. With the stock car, I think 8" is the biggest you can fit in the front, but need at least 4.5" backspacing. The back can take a 9.5 at max and still clear the fender well if it has 5.5" backspacing. The tire size will affect if it rubs too, so be moderate about how big a tire you use, but 240 and 275 will be a nice fit without pushing the limits.

Good Luck
Tim