ORIGINAL: fast9
Trying to get my YS 91 into my top flite P-47 and I need a 45 degree stack to get the exhaust out the bottom. I was told performance specialties makes one, is a bit pricey. I didn't see one on their website, but haven't called yet. Do stacks from any other engines fit this motor. I think the thread is 13mm by 1 mm pitch.
Go to your local welder and make your own. Fourstroke pipes are a nobrainer, no expansion chamber to deal with or special pipe routing. Might save yourself some cash.