Lookin at a new 40cc engine for my RCGuy Pitts. Its basically between evo and the zenoah. Any comments on either? The Evo is more money, about $150 more without the muffler. Worth the extra dollars?

The 26 redhead is about as strong as the zenoah 35. When you want the engine to pull hard at lower rpm, the 40 MVVS (evolution) will be stronger than the zenoah 45.
Horsepower wise they are about the same, but the 40 has the better low end torque, whilst the 45 likes to run smaller props at elevated rpm.

evolution all the way, I own a few of them and they are very dependable and strong but as you say they do cost more.

Hi!
My old (first version with alu crankcase) MVVS 45cc (Evolution in the US) turns a Mentz 24x8 at 6600rpm using the small MVVS canister silencer.
Can a Zenoah do that (Or any other 45-50cc engine)??

Mine can do it. Evolution 45 on MTW cannister,