I'm trying to help my brother out, he also has a '66, we already have the tires wich are, for the rear: p245/60/r15, front: 215/60/r15 and pretty much would like to put those tires on some Mag-Slots that I'm still looking for to buy and would like to know what are the ideal Rim sizes without the tires sticking out the fenders or rubbing on turns...

 

welcome to TMS. I don't know about the offsets but if your going to stagger the tire sizes you should also stagger the rim widths.

 

Thanks Glenn, yeah, the rim widths are going to be narrower up front for sure, still wonder about the offsets...

 

I don't think you can run much more than 4.5" backspace on the rear rims. A 245 is also about as wide as one could fit in the rear fender wells too. I guess that depend if the car is lowered or not.