RE: OS 33GT Gasoline Engine for Pattern
If you have plenty of time and patience - try different header diameters on Ed's pipes - they are the best out there - my opinion but you have to match the load (prop) with desired rpm.
Two stroke engines -used as a prop power source- often need plenty of carb fiddling -to get smooth midrange to full rpm transition- (some think this is a torque increase -it ain't)
as a suggestion- use the smallest carb which will produce a max power you feel necessary.
We had all the ZDZ40's and any of Ed's pipes we needed -a few years back-
the combos eventually worked vey well - but each setup took some tuning.
the generalization of about 28" to pipe baffle on the 40/50 sized pipes worked very well.
Power ?
gobs of power - but -takes a bit of thought and patience to get best results.
Peak power may be down a little once you hit best prop/pipe carb-
Mine were one flip engines and I also used 33% syn oil exclusively- more tolerant of heat
Being old n lazy - I fly only electric now - but the gas DOES work