So, I ran some numbers and did some graphs. Compared to a .40 size engine with 9.5mm diameter poppet valves, my ports should flow better, just based on cross-sectional area. Not MUCH better though, which made me think of ways to revise my design to get even bigger ports. I'll have to draw my new idea so I can make sure it's physically possible, then run some more numbers and graph it to make sure it did what I wanted.

I'm still pretty sure my original idea would work well, since there's no obstruction in the path of the gas flow. It's like dumping water into an open hole vs. one with a valve face sitting in the middle of it.

I haven't even cut metal yet, and this is already FUN!