Magnum swap questions
Actually the LA360 pans have a smaller seal than the LA318 pans. It is the main bearings that are bigger.
I was looking thru the Comp Cams catalog and I see your dilema. You can't use the retro-fit and replacement LA roller cam because they are for 1.5 rockers and have oil holes in the #2 and #4 bearing journals. You can't use a Magnum roller because they have the short snout. You are going to either have to run an electric fuel pump or get a custom cam ground possibly.
Chuck