Jon is correct about the MVVS. It is a powerhouse of an engine available as
a .61 , a .77, and a .91 all the same physical size and all can be run as side or
rear exhaust simply by turning the cylinder before you break it in. I have two
.77's and they both run great , very powerful with instant acceleration from idle
and they don't need a pump. I don't like the MVVS tuned pipe as I feel it is too
loud, too big , and too heavy. I am using an ES composites carbon fiber pipe
which is much quieter and produces more power , looks good too. The MVVS
engines also do not require high percentage nitro fuel to produce their power
in fact they recommend no more than 5%.They are my favorite 2-strokes.

tommy s

PS: I am still changing to a 4-stroke in my Widebody.