Jon, the camshaft below will give your .52 the torque and responsiveness your looking for! O.S. part # 45262050, it's the cam from the .40 car engine. The timing and duration are such that people will ask you again and again, "that's an O.S. .52?" I think my .52 benefit more from this cam than the .40 car version did!

http://www2.towerhobbies.com/cgi-bin...?&I=LXWY82&P=7

I picked up a couple more last week for later projects!