the best way that i have found to do it is to take a set of old steel valve covers, cut the top out, bolt them on and then start the car. once it warms up and the ticking begins, just start adjusting. It's not an exact science, I've never read it in a book, but an old timer showed me once and its never failed me. The way he put it was, " a rebuilt engine is only as good as the guy who built it, and no two guys build the same. So once in a while you need to tune an engine to its spec's, not the spec's in the book. "