Maybe I've just got lucky. The 3 swaps I've done I used the stock rubber/steel magnum gasket and la pan with no leaks. I wouldn't say you can't use it lol. Works for me.
Just curious, did you run the LA pan with the LA timing cover on all your swaps?
We run Kevko pans. Not the cheapest but great quality. Using the LA timing cover, you can take the "U" shaped gasket from the LA timing cover gasket set and cut the "U" off Magnum oil pan gasket and use some Rite Stuff where the gaskets meet. Always been leak free.
