Re: Going from 3.23 to 3.73 Diff Gears
I dont know whether this will help you or not, but i will post this anyways
I used to have 2.92 gears in my XD (302 toploader) and went to 3.25 gear set. I found that i got better fuel economy (go figure, probably because it takes less torque or force to move that amount over a certain distance). Take off was noticeably better (from losing to a vx by about half a car length, and then beating it by half a length). But there isnt much change in the highway cruisyness, i found that it was still very drivable, although your going for a more dramatic gear change.
Hope that helps.
FOR SALE: 1980 XD, Recently rebuilt 9" disc diff, with 3.25 gears, toploader with hurst shifter kit, 302C, DBA slotted and cross driled rotors, Fairmont interior with modified centre console, jellybean mags, reasonably good condition, driveline will handle 400+rwhp PM FOR PICS asking $3500