ORIGINAL: davewallace
Mark,
The Brillelli would be the one which would benifits most, because it is a less expensive engine. Any gain would be small, compared to the effort. Since both are purpose built engines, the port sizes and timing are already optimized for our use. Experimenting with props and carb tuning will give a greater return for your time.
Dave
Well, the gains would be for free except my time. This is a sort of winter project to keep me from going stir crazy and it really isn't that hard to pull the cylinder and do a simple clean up/match with the dremel and trim the gaskets to match. An easy weekend would get it all done with no sweat. Re-cutting the head is a much more involved chore and I would only do it if I had lots of time on my hands or it was WAY out when I checked it. I agree on the prop/carb/exhaust tuning, it definitely pays the biggest dividends for the time. But I hate to leave something on the table when I know it can be better with a bit of effort....
Mark