[Jim L]

Thanks for the info.
How many miles? Do you have access to a smoke generator tester?
When you say leak down, do you mean two gauges showing differing pressure? What's the input psi? Where do you hear the air leaking out, carbs? exhaust? case breather? I'm still not sure it's rings; a valve can cause the same symptoms.

If it is rings, either manual will be quite satisfactory. You will just be getting the parts off and to the machine shop for them to measure, bore and hone. Then all back together.

As an engineer, you should enjoy the experience. Let us all know what you find and how the tear down/build goes.

Cheers,