Originally Posted by JimC
I found when I went to 3.73's and tried to build the 7.5 up that it ended up costing me more than it cost to swap to the 8.8 when I broke the 7.5 rear end with just a CAI, tune, and a pair of drag radials. The supposedly indestructible Richmond gears (that whined like crazy) weren't - bent the pinion within 8 visits to the drag strip.
I've heard of a lot of guys blowing up the 7.5 with just mild power adders, some with only a 3.73. I think it's about your comfortable risk factor. If you can find a cheap junk yard 8.8 with higher gears, that's the way to go, but even that is expensive.
you might be safe with a 3.73 if you are just driving streets, not racing. There are some who have run 4.10 with posi dragging and never had an issue, but I wouldn't...
also, if you are an automatic, i've heard of people having trouble with low top speed...
---------- Post added at 01:43 PM ---------- Previous post was at 01:40 PM ----------
oh, and i did look into doing this myself once, I checked with several shops both big towns and small and ranged from $450 to $650. It's cheaper if you get the bearing kit and they don't have to mess with saving your old bearings (make sure you tell them when they quote you). Make sure whoever you take it to does a LOT of them, if they do a bad job, you'll tear it up.