I have the aluminum 113 heads, they have bowl work done, and the valves were replaced with 21-2n stainless, undercut,swirl polished valves. I really am not all about absolute horsepower as the engine will most likely do duty in a streetrod, and I have really loved the power and street manners from my zz4 engines. When I bought the engine, it was using oil like crazy. On teardown, I discovered that there was no noticeable ridgeat the top of the cylinder,and no scratches in the piston bores, but later discovered a ridge at the bottom of the bore. Upon dissassembly, the pistons just about fell out of the cylinders! I had not seen tiny oil rings like this before. I upgraded to the Speed pro pistons to get rid of the metric low tension oil rings. I had the calculator to determine compression ratio increase, but lost it. I know with the stock bore and the 58cc chamber I would be at 10:1, what does a .030 overbore and .005 resurfacing gain in compression?