I know I had 10" 350 and replaced as I felt they were to much. I have new 12" 275 in my basement. I think the 12" to long as the lower perch won't clear the wheel/tire (245/40-17 on 8" wide SN 95 style wheel). Can't check it now as car still at the shop waiting for the engine rebuilt to be complete. 18 weeks and still counting. It's killing me!!! and now it's SNOWING!!!!!!!!!!!!!!!!!!!!! May 10" 275??