[thekid54]

The engine in the '63 is most likely a 230 c.i. IIRC there are 2 families of straight sixes that Chevy/GMC used. The 216, 235, and 261 are all similar in design and alot of the parts will interchange. the other family, the 230, 250, and 292 came around in '63 and later. They are similar in design and alot of part will interchange. Going between the two families, you won't find much compatibility. Heads are different, motor mounts are different, etc, etc.