What size engine for the online/Youtube EC?

Irrespective of actual displacement, I think the larger bore will flow better with less shrouding around the valves.

I think the bore stroke ratio stuff is very secondary to that.

What was the thinking behind allowing mushroom lifters? Who's doing that these days?
I've always wanted to see a build with mushroom lifters--no other reason, they are always outlawed and I see no reason to outlaw something that probably doesn't exist anymore. J.Rob