Advice on stroker build with cracked cylinder

Wyrmrider said
not 100% if you are getting backflow as the ling rod piston travels up before the valve closes
at some point rpm and intake velocity my get you more VE till you run out of flow (cam, heads)
it also varies with compression
Vizard writes about this- I'll see if I can find it

Because of the delayed intake closure, there is considerable piston motion up the bore from BDC before the intake actually closes. This, at low rpm, pushes some of the mixture back into the intake manifold. This means the volumetric efficiency (breathing efficiency), and thus the effective displacement of the cylinder, is well below 100 percent. In other words, a 100-cc cylinder with a static CR of 10:1 may only trap 75 cc of air. This means the dynamic CR, at about 8.5:1, has dropped well below the static CR of 10:1. The bigger the cam, the more this effect comes into play.

Again just thinking out loud... I agree Wyrm - but the "100%" I'm talking about is simply the intake charge from my perspective. Yes, there is a moment where the piston coming up will push the mix up the intake - because there's no intake inertia present at 150rpm. So I guess it really comes down to "percentage of what?" are we talking about. I say 100% simply because there's a full volume above the piston when the intake valve closes but you're right in that the content of that 100% might be a little messed up. On a running engine at idle it would be dilution from the leftover exhaust gasses. At 3Krpm it's not going to have that dilution, and at 5250 it will be more than 100% filled by burn-able mix. At least I think so anyway. Back to the shop for now...