My home inspection of Speedmaster heads

too cold a plug in my opinion.... loss of power in my opinion too.... but just my opinoin
I'm creeping my way up onto hotter plugs. It's just what the recommendation of the machine shop that did some of the original work on my motor gave.. I was having problems with run on due to the higher compression of my motor.. ultimately I found out I just need more octane... As you know I've been getting it more street friendly so I can enjoy it more and get more familiar with it to diagnose...