ok here's what i'm looking at. i would like to get a set of zr1 type wheels for my 77. the ones i'm looking at are 17-9 1/2 with a 56mm or 38mm backspacing. i know i can get a spacer that will make up the difference and allow me to clear the calipers but what size spacers? and will these stick out of the fender with the extra room of the spacer? i'm also thinking 275 size tires in the rear and 255's up front. will anything rub? any help is appricated.