MATT, DAVE - Granted normal paint will burn off the hotter parts of the engine fins but on a working tractor I would not paint the cooling fins. It's Amazing how a very thin layer of oil, paint, rust, etc. will slow heat transfer. I also wouldn't paint anything aluminum, head, bearing plate, or the oil pan whether alum. or cast iron. Carb's normally weep just enough gas that the paint peals quickly so I keep them bare also.
Best time to paint an engine is after assembly IMHO. I painted my K321 a couple years ago with thinned down satin black enamel with a brush about 1 inch wide. It looks great with the shiny gloss black powder-coated air cleaner cover, cooling shroud, head cover, governor hardware, etc.
JOSH O. - What Kendell is talking about is the stress & vibration from operating the engine on that LONG piece of tubing. You look closely at the block casting of a Kohler and there's not a whole lot of metal holding the exh. port to the rest of the block. The top deck of the block and a very small round section where the valve guide gets pressed in is about all that holds the port in place, they try to keep as much heat out of the engine as they can. Exhausts much more than 8-10 inches long should have another support on them.
