Check the timing at idle, 1500, and 2200 rpm. If you do not see a change, there is your problem. Check vacuum advance while you are checking. @Where is the distributor vacuum hooked up? ported or manifold?
A really lean condition can make tons of heat, this goes back to the timing issue. How does it start? easy, struggle, spins easy, pulls starter down? How does the exhaust smell?
If you want to run your flat shroud, cut two large cut outs in the dead zone and put soft rubber flaps over them on the out side. Going down the road, the wind will blow them open. At idle, the fan wil not be able suck them open since they are on the outside of the opening and bigger then the hole.
Joe
vacuum advance is working. vacuum is coming from manifold not ported. starts and runs great. right at 5 btdc. i held the chokes on and cause a rich mixture. plugs were wet when i pulled them after this. results were the same. I agree with cutting the holes with flaps. my race car has the same set up. with the lower section of the fan shroud removed i don't think that is an issue???