My logic may not be sound on this, but this is how I see it.

Even at max flow, whatever that is, if the head flows that amount for a longer duration, there's more fuel in the cylinder to burn. Same bore, just more stroke, there's more fuel in that chamber. We get away with stupidly high compression ratios with normal mope heads, because we can't fill the cylinder. A PS head would detonate to death if you ran a static of 16+:1 compression. Whereas some of the highest NA numbers I've made with a mope have been close to 17:1. I think a static 14:1 in a 99 head would have higher dynamic, than a 17:1 best available normal mope head.

At some point these minor increases would get over run by parasitic loss, but I haven't hit that using the standard junk most of us use even at 5.125 stroke.