Swapable:
Valve covers, water pump, timing cover
Not swapable:
Intake(wrong width)
Oil pan
Distributer (different height/oil pump drive)
Maybe:
Balancer
Flywheel/Flexplate
All 351s balance at 28oz
Early 302s balance at 28oz, Late 302s balance at 50oz
The change happened around '81 if I...