I didn't have any luck with customer service at Edelbrock. All I wanted to now or to tell them was what I had found in my heads.
The answer was that "they are race parts and that you are expected to rebuild them before running them, so what did I expect".
I bought a set of S/B closed chambers and had to to a complete valve job because the valves were out as much as .008 in some seats.
then setting up the rocker geometry is another story.( you can't run any factory rockers correctly)
For a bolt on head, it certainly is not.
A pair of heads at $1600.00 ended up costing $3000.00 in the end to get them installed and running, and I did the assembly work.
Custom shaved lash caps, aluminum rockers, smith bros push rods,TTI headers, (69 340 manifolds don't fit.)
I just wanted a new set of heads for my 360,it's not all the goodies I had to install to get them to work it was that they are advertised as a stock bolt on.
I would not just bolt them on with out doing a thorough check.
I don't claim to know a lot but that's what I do know.