Promaxx new iron mag heads, good quality

You did not say what you wanted to use them for. If it’s for a stock replacement they will likely be fine once you get them checked out by a competent shop for valve guide clearance and valve sealing. Don’t skip this extra cost unless you can check it yourself.
I would guess these are very similar to head castings two other members here had threads posted for.
Here is the latest one. Can’t find the previous one yet.
Speedmaster magnum inspection w/Justin