some guy just put these pics up on Pirate4x4, he used the dodge x-member I talked about, and cut it down so it'd fit inside the Chevy framerails:
It's kinda dark, but the x-member is sorta contoured to the top of the t-case, and the bolts come up through it.
EDIT: was just browsing through eBay and found this pic, which shows even better how it mounts:
actually, this whole dodge frame is for sale in Michigan, maybe you are close by?
http://cgi.ebay.com/ebaymotors/1970-...spagenameZWDVW