changing the piston and jug is all that's needed to make it a 32, the cranks are the same, the crankcase on mine started out as a 28cc.

They aren't light engines, but they're good runners, the crankshaft is most of the weight of the things, you can shave off all of the aluminum you want and it will barely make a dent in the weight, the crank threads are 7/16" instead of the normal 5/16" on trimmer engines, and after the taper they just get bigger...