I am installing the engine on my mach II and ran in to a couple problems. First, the throttle rod is not long enugh to reach the carb. Second, it seems the OS .46 I'm putting on is bigger than what they figured so I can't install it as far back as they reccomend. The instructions say 4.3 inches from the inside of the firewall to the back of the spinner backplate. Well with the hole they provide for the Mixture adj I can only get it to 4 1/2 and it won't go in any furthe. will that make a difference in how it flys?