[Dangerous Doug]

Perfect. I had heard of the putty method, but when the valve presses into the putty I couldn't think of how you could measre the remaining putty. The obvious sign of trouble is seeing a valve imprint that revealed piston metal, but the razor blade trick can get you a clear measurement. The zero lash makes sense as well.

When installing heads do you adjust the rockers to zero lash? I know it's important to measure the spring compression by measureing the clearance between the spring bands, but what do you look for in terms of spacing?

Thanks again, David. This is good stuff.
DD