He failed to mention that all heads out of the box are first checked and corrected before assembly, cause out of the box, they aren’t right.
I like that he offers engine refresh services for all his customers engines https://www.shafiroff.com/rebuild.php
Shafiroff inflates his HP numbers, as my friend has dynoed several of his engines and they are typically 5% to 10% light. We call it the HP exchange rate when crossing the border.
That's were a good part of the GP comes from after all. Happy customer = Repeat customer. That's a good one 1320feet....I'm sure the weight/MPH tell the story right from the get-go in most cases.
So many variables involved in dynoing a motor. I haven't dynoed a lot of cars, but I have dynoed many, many bikes, and I've found that no two dynos read alike. Never mind the hundred other factors involved in small differentials in peak power production. When working toward developing horsepower, developments can only be measured on the same dyno over and over.
In season 5 of Motor Trends Engine Masters , episode #25 " Rod ratio explained " . Dyno operator Steve Brul'e mentioned that he dynoed a set of twin BBC engines for a speed boat and that there was a 10-15hp difference between both of them . He also mentioned that the engine builder who built these engines built them identically using the same parts and assembly tolerances