[Chuck78]

This is for the 60's era heavy duty, truck/heavy-equipment-only big block V6 engine family. The trannies are the same, the block to bell pattern is unique to the GMC V6's, V8, and V12 of the era. The adapter to mount an auto trans (obviously integrated bell) to the GMC engines is $1000. Engines were 305, 351, 401, and 478 in the V6 (and two others like 379 and 43-?, more rare and beyond the 60-66 passenger truck line useage), as well as a 572? V8 and the 702? V12 that used 4 V6 heads and two V6 intakes, one block/crank/cam.

The talk of NV4500 adaptation to the GMC truck V6 is I believe due to the 4500 having it's own bolt pattern, trans to bell. You can run a Dodge version I think, with hte longer input shaft of same diameter, and use a cheaper adapter plate between the trans and bell for that application to use in a non-chevy block to bell pattern.