Good question. LOL
There was only one question looking for one answer. With that said your question took up the space for that answer....
And now you've introduced the third subject which is off subject and is your fault, know how many fingers are pointing back at you? LOL
Let's not "panic"... LOL
I do want to keep this on the Speedmaster heads as just even like 70AARCuda has given us some great experience with them but yet not complete yet. I would love to hear somebody as you put it one of those 50% that just put them on and had some kind of catastrophe? You know kind of like the eagle crank breaking thing? There's no blowing up engines stigma around these that I'm finding?
Also when everybody pon page two started going off on how much they can be ported or not I tried to just keep the subject on the reliability and quality out of the box.