I have a set of Cragar drag stars on my 68 camaro. Im running
front:15x6 205/60/15
rear:15x7 235/60/15 they might be 8 inch wide not quite sure.....

my question is what is the max size tires i can use on these rims. I once through a friends 15x8 with 235/60/15 on the front but never drove it cause they rubbed....but not by much. So my other question is with 15 inch rims whats the widest tires i can put both front and back...any rim witdth as well...stock suspension

Proper backspacing is the key to get maximum tire width with no rubbing. Is your car lowered? I have seen Camaros with 245 series tires on the front with 8" rims, but the fit is close. Do you know the backspace measurements of the rims? Take one off the car, lay it face down, place a small peice of wood or other straight edge across the rim; measure from the bottom of the straight edge to the rim mounting face (where it touches the disc/ drum hub). That measurement is your backspacing (in a rough sort of way). You can also stick the tape measure through the spokes of the rim to see what the width is.

For proper tire clearance on a 7" rim your backspacing should be about 4.5" with a 235mm tire. On an 8" rim I would go up to 5" backspacing and you could squeeze a 245mm tire in the well. On the rear axle you can get up to a 9" ot 9.5" rim to fit with a 275mm tire if you are lucky. Likely you will need a 5" backspacing on the rear with a those rims also.