I finally decided to go with a 4.250 stroke and build a 496 ci engine, i had my dad call comp. products(I never have time and they aren't open on weekends) and they said i'd have to have custom pistons made up for the 4.375 stroke and 6.535 rod, the tech suggested we use a 4.250(forged 4340) stroke and 6.800(h beam) rod, I don't know exactly what pistons he set us up with but the comp ratio came out to 10:1 with a 118cc head, the hole package came to $1,500 (whole rotating assembly rings bearings ect.) 781 heads should handle this with with 2.19 intake and 1.88exhaust valves, wanted to use roller cam (howards hydraulic roller lift .577/.579 duration @.050 222/234 lobe center 112) will the heads need to be machined for the cam (spring seats, guides) wanted to use a dual plane intake manifold or would it be better with a single plane, not going to rev it up very high, mostly be street driven, engine going in a 85 4x4 chevy truck 4 speed trans 4:10 gears, might get into truck pulling later on any input wouyld be great

thanks