Good news[&:]
I tore the engine down and checked things over. Looks pretty straightforward. I found what's left of my first attempt at a conversion; a McCulloch 35cc chainsaw. Too bad it had needles on the crank shaft. But, the carb is still worth a look. I took it off the enfine and checked it against the Ryobi. The Ryobi stock carb is actually SMALLER than the intake port on the backplate. My other carb from the mac 35cc engine was a drop-in replacement------only its the exact same diameter as the backplate port. That ought to pump things up a bit. The pressure holes for the pump line up perfectly and the linkages are all the same. Its about 2 or 3mm bigger than the stock carb. It's a Walbro WT 348 carb. It'll need a gasket kit, but thats no big deal.

I ordered a ring from Frank Bowman. What a nice guy!!! He talked me through the entire process of this conversion. His ring should help the engine out quite a bit.

I ordered the ignition from CH today. What a bunch of nice guys!!!

I'm going to try and clean up the intake ports a bit on the inside of the case. I just want to radius the edges a bit to smoothe things out. I'm not going to hack a bunch of metal out of the case, just radius the bottom side of the ports near the crank counterweight.

Where can I get a gasket kit for the engine? Or do you just make a new set from gasket material that you find at the auto parts store??