Also keep in mind with your thoughts dan true the 46 would out perform the 55 but the quickies were under four pounds. I think the 55 should out run it but would have to use a different prop like a 9x10.

high plains thanks for the update but I still think the St g-500 muffler was first. when did the St 40 Q500 engine come out?

CP those St mufflers come apart on the inside. the outer muffler casing is crimped on and you have to cut it off forward of the crimp to remove it.
also not knocking Jett engines either as they make pretty good power and will last a pretty long time. Jett best sport engines are the 35 and 56. these two are bench mark engines. The 35 does need its rear bearing replaced often though and the rod may not last long if ran over 21,000 on the ground. What i mean by that is the rods life span of is cut by 25% or so. it will still last around 7 gallons.