That's too much compression for pump gas. So yes, you'd have to change pistons to lower the compression. If ya do that, then comes changing the cam to work with the lower compression. It kinda comes down to how quick you want to put this on the street. If your not in a big hurry and have the time to try and sell what you have, then that would be the way to go. If you want to do it now, then make the changes on your 496. JMO
TS1955