I've used three of the industrial 413 H.D truck blocks to build 426 motors as well as afourth one for my 1963 Plymouth Fury with a 4.150 Mopar stroker crank in it, none of them had real thick cylinder walls after sonic testing them whiney
The first one had a external freeze crack that the machine shop didn't find when they magnafux it, it had a crack cylinder inside also work
I ended up junking that block whiney
On your deal I would have the crankshaft offset ground to BB Chevy 2.200 rod size and increase the stroke to 3.910 and run a set of 7.100 long BB Chevy type H beam rods with a set of custom pistons up scope Make sure and have the block sonic tested and magnaflux before starting so you can decide before starting what bore size, stroke, compression ratio and so on that you end up with up work

Last edited by Cab_Burge; 05/20/19 01:30 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)