Fleet: VECO 45 , Wow! I haven't seen one in years. T'was a powerhouse. I had a VECO 35 RC. Had a unique exhaust flap that would come down with the throttle to keep the heat in.
Ray, that flap was an exhaust baffle for back pressure so it could idle without a muffler.
I remember the model mag articles, concerns about power loss in engines by requiring mufflers, the aftermarket mufflers such as aluminum Tatones, Dubro's minimal muffler that could be made to barely muffle, and etc. Then some genius came up with Schneurle porting, better muffler designs and the rest is history.