No, I can not. There have been several engine changes, so only the factory can tell them apart by the number on the mounting lugs.
On the quickie, which has the same cylinder, I used header pipes up to 14cm long for a 9x5 prop. Header length and prop size are inversely related, so you can either use a smaller prop or a longer header if the engine will not get in tune with the pipe.
BTW, use 20 to 25% oil if the engine has to scream!