Maximum bore each block can take
 

I have a 351E with magnum intake, heads, and exhaust manifolds. Can it be bored out to 401? Are all the different displacement blocks the same dimensions?

Re: Maximum bore each block can take
 

The bore of the 351 is 4.56", bore of the 401 is 4.88". I don't think there is enough cylinder wall thickness in the 351 block to accommodate a 0.32" overbore! As far as dimensions are concerned externally they are the same but cylinder bores are different. The 379, 432, and 478 use the long stroke crankshaft.