Don't know if this will help but I'm running a 54 w/straight axle, 5 lug disc conversion (CPP) on the front with 235/70/15's on 15X7 rims with 4" back spacing. Theses clear both the stock tie rod ends as well as the upgraded ends by 3/4-1".
On the rear I am running an 88 Camaro 3.42 (62") with 255/70/15 on 8" rims with 4" backspacing. These are a bit close on the inside (box) but with swaybars and near stock ride height they work fine. If I had it to do over again I would go with 15X7's w/4" bs and 235/70/15's all the way around. The 89 Camaro IROC-Z diffs come with posi/discs but most are 3.08.
The Camaro diffs are only 2-5/8" tube diameter so you have to make a strap shim if you want to use stock 3" U-bolts. I have pics in my Webshots" Shoebox album that can give you some idea of the process and the end result. Hope this helps you.
Dave
