Andrew, my set up is a uniflow clunk tank, powermaster 10/22, thunder tiger 11x4.5, stock muffler or tongue, flat washers on the backplate screws with a drop of ca. My planes are a Primary Force, Teosawki, P-40 and a Tutor, they don't need the extra power of the .46. I think the weight difference is very small. I have plenty of la46 motors and i can't tell the difference in the runs except for a little more power and fuel usage from the .46. Best thing is i gave $25 dollars or less for each of them. The FP40 is the one i had to tinker a lot with to get suitable runs. I think you should give the LA40 another shot! Best regards, Ray