As far as going small block, you don't have to go with the horse shoe mount and hydraulic V8 bellhousing unless you're after originality. You can go with 67-72 motor mount perches or 73-87 3/4 ton perches, either need a small spacer as the frame is taller on the newer frames. For a bellhousing, you can use a new super easy to find, mechanical linkage style. I don't know what year of parts work to convert it, though.
I found this on Ebay a while back. I'm not sure if it is the 60-62 Hydraulic bellhousing or not, but sure looks like it and claims to have the right casting number.
http://www.ebay.com/itm/65-67-CHEV-G...5fe713&vxp=mtr
Hope any of this helps.