I've got an 87 5.0 with 3.55 gears. I recently installed a rebuilt T-5z, and plan to install some 255/40/17 rubber on 17x8.5's. What speedo gear will I need? As an aside, I assume (since the LRS website states "Requires a 1/8" spacer when used on all 79-86 cars or 87-93 4cyl cars.") that these will fit my GT without rubbing...?