gabe6090

Have a GS-40 on a sport scale Gee Bee. It's under-powered. I have a pitts muffler on it so I want to be able to use that on a new power plant. I believe that leaves me with two options, the ST 45 or 51. They show similar hp numbers but the 51 is quite a bit more expensive. The 51 is ringed while the 45 is ABC. Is there more to the story than them having essentially the same horsepower numbers?

Thanks

aerowoof

if it is underpowered with a 40 then I would put the largest engine that will fit in it.the .51 should turn a larger diameter prop or one with more pitch than the .45.I myself would look at maybe using an olser webra 61 blackhead.they are not much larger than todays 46-52 size engines but can swing a 11-7 to a 12-6 prop with authority and will handle a six pound airframe with ease.the crankcase width is 1.5 inches,length from backplate to front of drive washer is 3.5 inches height from bottom of engine lugs to top of cylinder is 3.125 inches.