While trolling ebay for goodies I saw an RC version of the 35 stunt engine it even has the 3 bolt backplate was this factory or something home brewed? Search for Fox 35 r/c

         That Fox is a early 80's version prior to the 40th anniversary edition. I have some that run quite well and others that are so so. The muffler is a Fox muffler which works a heck of a lot better than the worthless tilt down muffler that just makes your Fox overheat. That particular muffler alone has sold for more than what entire engines go for. The muffler in the picture will eventually fall apart when the back falls off and the guts get shaken out. Pop rivets or small screws can hold the back on reliably. Remove the internal baffle like element and you'll have a muffler that is lighter and functional. The other nice thing about the muffler is that it doesn't butt the exhaust flange it goes all the way over it. Not only that it fits snug and combined with a hose clamp for attachment it will fit all Fox.35's except for the 50 th & 60 th cases. Ken

That's kind of what I was thinking the front muffler lug looks like it was ground off to make clearance for the carb probably using the over & under mounts and the carb mount looks like a 15bb

Yeah, it looks a bit cobbled together around the carb bolt-on flange, and ground away for access to the carb mount screws.

??Cut off the stock Fox 35 venturii, heli-arc'ed a platform for the carb?? (...WHY???...)

And, the carb is from a 4-bolt backplate 19-25; it is rectangular. The schneurle Fox 15 carb mount is not rectangular, more a rounded lozenge shape.