Cooter
I run both of crankshaft seals and the cam seal (Jessel belt drive) in the normally installed configuration.
But I don't know how much vacuumn I am making or how much air inlet leakage their is either.
I do know that on the Dyno it was good for a disappointing 13 HP my Engine builder has seen as much as 40 HP gain but in those cases they used a different piston ring combination and turned the vacuumn pump faster. In my case it's keeps the alcohol from milking up the oil which was what I had in mind anyway.
