IF i am reading this right you say you are running a 327 crank with 350 pistons ???

A 350 crank has a stroke of 3.48"
A 327 crank has a stroke of 3.25"

The standard rod length of these 2 strokes is 5.7"

So therefor the pin height in a 350 piston is higher in the piston than a 327 by.230".

First thing I would do is do a compression check, see how many psi reads on the guage.