[GOSFAST]

This is aimed more at aluminum heads that have been in service for a few years.

This is actually a (Canadian) head from a member here chasing an internal water leak. Got it for pressure test and "Zyglo".

You can see from the photo all the irregularities that couldn't easily be found with a "straight-edge" and a "feeler guage".

There are a couple of very visible "lows" and "highs" across the surface that shows up easily with a very flat table (Bridgeport) and an accurate dial indicator.

Thanks, Gary in N.Y.

P.S. Based on our experience and those "recorded" numbers written on the head surface it will require about .014" to make it flat again!