Razor... sorry to hear about the flyaway! Have someone fly overhead in a full size and look for the glint of gleaming aluminum
Either of the engines, if you already have them, will run pretty well...... but put a Jett-Stream muffler on them instead of the full pipe. Its only about a 500 rpm difference (in most cases) and its not as critical on prop selection. Will tend to weigh less than a full header and pipe too.
I bolted at jett-stream on a friends Morris 45 (rossi) saturday. He had all sorts of problems...it had decent top end, but wouldnt idle or transition....he changed the carbs... all sorts of stuff. It appeared that his 'stock' exhaust system was leaking pretty badly around the o-ring.... was rarely consistant on performance..... it was hard to get a consistant needle setting....and if I recall that muffler is 'tuned' to run around 17K rpm....so it ran like it was overly 'short' causing the midrange and transition problems. I had a rossi adapter in my field box, so I took the muffler off of my SJ-50, and installed it on his 45. With the jett-stream it idled down nicely, needled great, and gnerally behaved very well....... plus had 15K on the top end with a 10x7. Not too bad. We did note that it ran 300 rpms less with the same prop.... on the ground. It definately unloaded better in the air.