one thing that alot of people don't know is that oldsmobile has a hemis chamber but the plugs are to the side. i have afew heads out in the shed and they have dome chambers, but they are shallow and the pistons have dishes. you put a flat top piston in one and you better have some good gas to run that monster, if i remember right somewhere around 13.5 to 1 to 14.0 to 1. that is why people liked to convert the diesel 350 to gas for racing.