Find out what size your rough bore is for sure, then worry about parts. Because, you can build a pump gas 423 ci small block for the street that can make 550 lb-ft of torque and 600 hp. So a 528ci pump gas Hemi for the street will go 660 lb-ft and 740 hp. Been there, done both.
Oh, going from 4.250 bore to a 4.500 bore is 1/4" over (.250").
