I would think that if you had a 4 mil stk cyl heavily ported that it would be comparable. But a 100hp 4mil stk cyl is a lot of work lol
As just a "dune port" I am not sure there is much info.
I have a nice ported 4mil stk cyl that I am going to maybe toss mine on and see how it does. It is ported 198/128 with 33pwks cool head, + 6 timing on 110/91 fifty fifty mix.
I will post my experience on it in a few weeks
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