You can get the same displacement in a 400 or 440 block. The 400 block is not as tall. I did a 496 with a 440 and I have hood clearance problems--would not be an issue if I used a 400 block. I'm going with a 400 block for my next stroker for the Charger. I've read the 400 block is stronger-more rigid. I don't know if it is or not.