Post your wheel and tire combos.

Well, I got out the tape measure and straight edge. On the rar of my 68 barracuda I could run a tire with 12" sectional width with a max of 28" diameter with the right back spacing. So 275/60r15 on 15x8 with 4.5-4.25" back spacing. This leaves 1/2-3/4" of clearance between springs and fender.

Tempted to try 295...