It's been 30 years since I wrenched on Fords (1970 Maverick 429 C-6), but I believe the 429 & 460 2-bolt main blocks were the same except for the bore (385 motors). The 429 SCJ blocks had 4-bolt mains and are much more desireable. The C-6 auto trans is very stout & should perform as well or better than a 4-speed. Get a copy of the Ford SVO catalog ... lots of goodies available for the 385's.