Well I won’t say I’m never going to buy another set of Speedmaster heads

Hate to lose the input of the knowledgeable members, especially those who have proven their abilities. I hope you reconsider John, even if it is some time before you do. I, like Rob and many others don't know bupkis about the science of cylinder heads, and I try to learn from those who are willing to share their experiences.
I even enjoy the Walmart pics!