Problem with oil pan gasket?
I just went through this myself with my 360 build. Never could get it to seat right because it appeared to be too long. So I cut a small section out of it with an exacto knife and then bonded the edges of the cut with The Right Stuff.
Also used RTV on both top and bottom.
I don't think it will leak. The Right Stuff really did a good job bonding the two parts.