Go to the Conversion Engines Forum here on RCU. Those guys are always converting Weedies and Chainsaws. They know just how much exhaust duration you can get away with and how much you can mill the jug down to increase compression without going to far on the squishband.

Matching the cylinder transfer ports to the case is not going to hurt you in any way. Just matching the ports will not hurt the engine. It will help out a bit, but I couldn't say how much. You know that if you take too much out of any transfer ports, then you are increasing the swept volume and effectively slowing down your transfer charge velocity. Thats not good, unless you stuff the case or make other modifications to counteract the larger and slower port velocity.

I think your on the right track if you just want to clean it up a bit. When you start raising transfer ports for increased transfer duration, or changing the intake duration--thats when it gets tricky.

Go to the Conversion Engines Forum and ask your question there. Those guys do conversions because they like tinkering with motors. Most guys who fly your off the shelf engines have no interest in modifying their engines.

1/2 of them can't even tune a carb.

[sm=47_47.gif] Did I say that out loud?