Torque plates work, and they're not that hard to build. I've used them for 30+ years on most of the engines I build. All it takes is a surface grinder, a drill press, and a boring bar. Getting that kind of horsepower improvement on a dyno run is total BS from nothing but a stress-honed cylinder, however.
An 18% leakdown rate on a cylinder balance test is an outrageous assumption. If an engine has more than 10% leakage it's time for a rebuild.
Jerry
