I have one of these engines and it runs like a champ. I've currently got it in a QQ 23% yak and it does a great job. I ran mine in at 32:1 lawnboy for a couple of gallons and then switched over to Mobil 1 2T synthetic at 50:1 and have no problems. I also use premium 91 octane in my engine and get 8700 rpm on the ground with an evolution 18x6 and 8450 with a Xoar 18x6. The Xoar is less static rpm put pulls like a horse. I know guys have posted on here that they can't get high rpm numbers w/o a tuned pipe but I'm running the evolution inverted pitts and getting really good numbers.

For the most part I don't think it matters if you run it in on petroleum based or synthetic base, synthetic will just take a little longer to seat the rings. There are plenty of guys here that run the 50:1 amsoil and don't have any problems. I also know some guys running 32:1 synthetic without issue, I just personally think that's a little too much oil for it.