it won't work.
2 reasons it doesn't work.
magnum engines all use the 360 size seals.
5.2 or 5.9 are the same pan and gasket.

but even if you got it to seal, there is a lot of gap to seal.
Feets will tell you I am an RTV fiend. I will use a whole tube of the stuff on each side.
I used it on a 360 pan for a 5.9 and it still will pour oil out of the front and back.

I haven't looked in a while. but they did make a 1 piece for sb a while back. for the la type engines.