As far as I know they are iron 8 bolt heads just like the factory iron 8445 castings, however, they have improved intake and exhaust port flow, a reinforced deck structure, and air and heat crossover eliminated according to this--------->
I know Red is using these on Jane's car (he had a set ported by Champion) and they seem to work very well...... I'd guess they cost around $1000 or so, but I really think a good set of ported factory 8445 heads from Champion or Nick Micale would flow just as good
I thought the A heads were bigger than a stage 1 but not as big as a stage II. And there were only like a dozen sets cast or something???? Was there just an A at the end of the part # of a stage 1 head???
The stage 1A head was thicker, had bigger ports, and could take a bigger valve, they also had stud mounted rockers like a chevy.
There were about 50 sets made I have only seen 4 sets ever and 3 were in one place. I bought a set which I sold to Terry Houston who, I believe, sold them to Red. If I could could find another set I would get them in a minute.