360 now 408 stroker oil pan still leaks!!

Are you running a PCV valve? If not, try it out. If you are, change the valve. I'm thinking that you're having pressure building up in the crankcase, pushing oil out of the crank and pan seals.
I still have the original pcv valve and I'm planning on putting it back in. I picked up a chrome one from a speed shop this summer and have been using it and that might be one of the problems. Thanks