Notice here what looks like a chrome washer up against the head. It's an .080" spacer to account for differences in the heads. Dave Mackie was initially going to touch up the stock heads for me. Nothing fancy. Not wanting to do a lot. Biggest thing was improve a hot spot around the exhaust port that's not ideal to begin with.
When speaking with him about the job, however, I mentioned that I had a pair of newer heads from a 96" motor. "Use them" was his immediate response. I wasn't looking for huge perfomance gains here. The man was honest enough to talk himself out of some extra work saying these would be fine for my purposes. All I did was go down to a buddy's local machine shop one evening and give them a fresh valve job.
The new heads, however, are "shorter" at the boss for the breather mount than the older heads. That's why the spacer is there. Necessary to fit the breather.