I should have some real work Stealth Head info fairly soon. Maybe I should chassis dyno the car before and after doing the head swap. I'm just waiting for the rocker arms to arrive.
I know a few people running the heads out of the box with no complaints, but I have read the really early batches had some issues with locks/retainers? The ones on my heads look fine for my application?

I have done the rebuilt/ported 906 heads before on my old 383, and it was more expensive than I though it was going to be. It was mostly labor related costs:
Clean heads, surface/mill heads, replace valve guides, install exhaust seats, port heads, multi-angle valve job, and cut spring pockets.
Plus all the parts:
New valves, valve guides, exhaust seats, guide seals, core plugs, springs, shims, locks, and retainers.

If I was a machine shop, It would makes sense to tell you to re-use your stock stuff because they make more money selling you the machining labor.