You are looking for a good, powerful, reliable engine.  I have one that I took out of my boat last year.  It is a .060" overbore, 4 bolt main 454.  Steel crank (std.), H.D. connecting rods, 10.25:1 forged pistons, Brodix BB1 aluminum heads, Jesel rocker arms, Crane Saturday Night Special camshaft. Complete, intake, starter, flywheel, oil pan, fuel pump, balanced.  Used, but not abused, and not worn out.  Takes up space in my shop, and $'s tied up that I can use for my new engine.