Since you are in the "twittling the thumbs" mode why don't you think about putting some small scoops over the screened air inlets on the sides of your body? Might help get a little more air to cool your motor.
I do love your wooden body, I am not sure if you should ever change it.
Rex
As far as adding scoops, at this point I'm almost afraid to add any more cooling effect. With the added piston clearance I'm really banking on the engine running hot to make the most power. It's an old trick from my demo-derby days, build the engine really loose, then when the radiator gets knocked out and you loose all cooling it will still run and make good power. At one derby we ran in the heads were actually glowing very dull orange and the engine was still running at the end of the heat.
Of course, that engine burned a couple of quarts of oil before it got up to normal temp, we had to warm it up in the pits and then top off the oil before the heat started, and it rattled like diamondback cold too.