So you think I'm off base ?
Take a set of old iron heads to your favorite professional shop.
Shop labor at $ 100 or so an hour and parts.
Do the math, it's going to add up quick
Don't forget pressure testing and flow bench time.
AND you are a VERY regular customer you MIGHT get that local machine shop to agree to do those iron heads for you. If you have a YEAR or so to wait…Swingn’