Stay away from the 4.150 crank in the low decks unless you use something shorter than the 6.76 rod. There’s not enough CD on the piston for any real longevity out of the rings (I know I ran one). I’m partial to the 512 kits myself if spending the money ( I’ve built 3 of them with source kits). Great combo, big torque, drops right into the block with just a touch off the oil pump boss, and they don’t cost anymore than the smaller motors. You may be able to peice a 451 together slightly cheaper but it’ll take some leg work.
