Pan vacuum question
 

I'm using manifold vacuum for pan vacuum and my fresh engine is a little down on pan vacuum compared to last year's engine. Last year the pan vacuum would creep up to a little over 6" and this year I'm at about 4. Seals are not in backwards. Before I put the engine in the car I put a vacuum pump on it and I could hear it leaking at both crank seals. I used a Felpro viton single lip rear main, 2918 I think. It's the same seal I used in the last build. Is there any chance the seal improves with some run time, like it burnishes or smooths on the very edge?