I have been working with the Evolution .36 C/L engine on and off for about 4 years, with limited success, but just enough to encourage me to swap a ST34 for a 2nd Evolution. I had tried my own venturis, various prop loads, fuel mixtures, decompression and glow plugs with some occasional success, only to find the engine to be inconsistent.
This Summer I finally decided to check the cylinder port timings and I discovered that the exhaust duration is 150 degrees and the intake ports timed for 30 degree blow-down (total difference between intake and exhaust). The data I collected from researching stunt engine tests in Stunt News and other sources revealed that typical cylinder timings for stunt engines generally vary from 130 to 140 degrees exhaust and approximately 15 degrees blow-down. I'm stuck with the crankshaft timing as I cannot change it anyway.
The best running stunt engines I have are around 140-145. The 40VF varies but it's around 142-145. The "Brett" version of the RO-Jett is 144 (at least thats what they are supposed to be) and it is the version that runs the best. Others have 140 (OK but not as good) and 136 (not nearly as good). The lower the exhaust duration, the more excessive the power change in maneuvers and the bigger difference you get between 2 and 4 if you let it transition.
They also have very aggressive crank timing. I am not sure what you would want change on the EVO but it's pretty easy to make it wider if you need to.
The blowdown does seem excessive, but I don't have good numbers for that.