Well that's why I'm asking for junk heads. I don't want people's good parts to waste.
Again, opinions and theories are great, but how can anyone give a 100% true answer without being witness to tests and experiments? I'm offering to pay for junk heads, that's all. I have the equipment to do everything I need. Lasers, Waterjet, CNC Mills and Lathes. I just need a couple throwaway heads that I will happily pay for. Definitely more than what they're worh in scrap.