Factory Magnum plate is different from LA. They should not be interchangeable. The Magnum block is machined to a different depth. I forget which way it is, but one plate on the wrong block will not compress the gasket and will leak.
I do not have either version of the Canton aluminum plate to try, and have never had one. So I guess I will double check the LA fit on a Magnum after I get one, but I have no idea when that will be. I need other parts first.
