Thank you for the replys. I have the four stroke installed with a new 12oz. round sullivan fuel tank to allow me some more room to run the throttle over the tank. That and I didn't like the tank that came with the model. It kept getting air bubbles in the fuel line. Didn't want to mess with it really at least not at this time. I couldn't use the engine mount that came with the Mach 1 as it wasn't long enough to give me the space I needed for the carb behind the engine. I used my SF engine mount I took off my Super Stick and it worked like a charm with a little drilling of new mount holes and moving the nuts over on the firewall. I have 4 tanks through the motor 3 of which I did on a test stand. Thing seems to have a good amount of power with the 11x7 MAS prop I have on it. I ordered a 11x6 and 11x7 APC prop for it as the LHS didn't have any in stock. I plan to go out in the morning for it's first flight on the four stroke and I don't forsee any issues. I would have to say the hardest thing about changing over to a four stroke was the carb placement and it's control linkage placement being in the center of the fuselage. I'll report back on how it ran and my impressions of it over the 2 stroke.

Compared to the HB engine it's actually smaller in physical size. It might even come in about the same weight. I couldn't tell a difference by hand. As I've read the idle isn't perfect yet but it's not broke in fully yet. From what I've read over the course of a gallon of fuel the idle will stabilize and clean up. I did have to adjust the valves as they where a tad on the loose side. I set them up at .003" cold and checked them again after I ran it WOT for a few minutes. The motor was at 280* and they still had about .001" clearance so I think it's pretty much perfect atm. I didn't bother with checking the cam as it runs good and I didn't want to tear it all apart. I'm surprised at the internal finish of the ports on the head. I was figuring I was going to have to do some porting and finishing of this cheap engine, but the finish is excellent.