Hey! 306bullet. I hade use speed pro plasma moly for many N2O engines and many hasting sets of rings on normal or charge applications even on EAVYDUTY WORLD (trucks, buses etc.) hasting is the way to. hasting even some applications for tactor that are hard to find from other manufacturers I personaly think with all due respect your machinist is not too sure of what he is doind so he is trying to cover his rear in case of something doesn't turn out right. if every thing is done right at the machine shop and assembly is proper you are going to have a good lasting engine. hope that helps