all bbc say hi per or truck/pass and some say truck /marine they all work your engine to make 500 hp .the block crank and rods is about all that i would use and maybe not even the rods or crank i would build it to a 496 they have a better resale for me and not much more$$ if you need any crank work look for better heads less you build for max Tq there many parts you can buy and many ways to build it