SIG- I've purchased a 14 bolt rearend from a later model Chevy for my 3600. The Ford rearend may be a little too wide for your truck if you're planning on keeping the origianl truck bed. You need to find a rearend that's 63-65" wms-wms (wheel mounting surface). Most late model rearends are 65" and wider.
GM made a 63" wms for dually trucks, that is pretty much the perfect width for your truck. I'm actually using a rearend out of a SRW (single rear wheel) truck which is 67" and using dually hubs to narrow it up to 63". The problem being is that now I have to get creative with the brakes. I'm doing a disc conversion, so it's no big deal.
If you can't find a dually rearend, you can always use a 67" 14 bolt rearend and use your hubs off the Eaton. It'll give you about a 65" rearend. Then all you would have to do is weld a new flange on the rearend so you can reuse your original backing plates and drums.
http://s1074.photobucket.com/user/w...amp;_suid=136629145223703088780721707863http://www.pirate4x4.com/tech/billavista/14b_bible/
