ORIGINAL: combatpigg
I've got a couple of project drawings that might help, but there's no substitute for having an engine in your hand to size things up with. I just attack the model with a "rasp bit" on a die grinder when it is time to clear the exhaust, then glass the gaping hole back up after the model is built. It helps to have a 1/2" thick balsa sub-firewall behind the plywood.
Isn't a chainsaw blade about the right thickness to cut a tunnel for the header...? You could do 'er in one quick swipe.
Yeah, I'd like to have examples of those engines but I don't for now.. all I have anymore are these lousy Italian speed engines [&o].
MJD