the killers for performance on a big cube motor in that combo are, the small carb, very small heads, small intake manifold, and poor exhaust.

while you can use any year or size OE block......the heads, intake manifold, and exhaust manifolds MUST be the correct pieces for the original combination.
the carb doesnt have to be the correct part number, but it does have to at least start out as something that was the same size as original.......and in this case, that means "small".

trans and rear axles arent going to be the problem.
making power with be the problem.