RE: O.S engine question
8, that's a good point. AX's really don't seem to like turning up those really high rpm numbers. Well, the 55 and 75 don't. I'm sure the 35 and 120 don't either. I've seen someone running a 46AX (I've owned like 4 of them) on a tuned pipe with a 9x9 or 10x8. It SCREAMED. If you pull the baffle out of the stock muffler, it also helps. OR the tower hobbies muffler. BOY does that muffler help!
Regardless, my 46AX's have been the BEST engines I've ever seen run. They're the most durable little suckers out there, reliable as all else, and powerful to boot!