OK, I'm adding this post here since this involves a Fox .46. I dug into my junk parts bin and came up with a useable Fox .50 cylinder, piston and ring. I have a well used .46 ABC with a slightly loose rear bearing, I slid the .50 cylinder into the .46 block while rotating the cylinder so the ring would gently adjust its self and go in. And of course I went against all logic and put a Fox Quiet Muffler on it. I used the same carb as on the .46 above since it was already set up. I first ran a MA K 12x5 for an easy load and good flywheel effect then changed to the Taipan 11x7. It holds 11,000 plus rock steady as long as you want. The Davis head is quite old and well used but that doesn't matter at all. On this one I could run the carb at full open. This set up runs easy and smooth, idle is for as long as you'd like with no burble from cooling off. Atta Boy Dave, and I just broke my own arm.[8D]