The red head that's on the engine now was done by Gaerte. It's a stock head that has been ported and polished with big valves and roller rockers and so on.
Because it's stated over and over by a very few people on this forum that the inline GM heads have no performance enhancement potential I've gotten interested in that subject. There is no perfect product that I've ever heard about in 75+ years of life so the "Porting those heads is a waste of time" rap does not have the ring of truth to me. Do you know of any articles that describe modifications to those heads and before and after tests.
I once had the honor of meeting Harvey Crane at a Southern California Timing Association meet at El Mirage dry lake on the Mojave Desert of Southern California. He was there with a Buick straight 8 powered car and he told me how much potential he found in improving that head. Presumably the same potential exists in the Chevy/GMC also. I just have an academic interest in learning what there is to know on that subject.
I've also been to the Bonneville salt flats to spectate a few times. From that I learned that tiny improvements to engine power and vehicle aerodynamics result in new records being set on a regular basis. A good friend of mine campaigned a Ford flathead 4-banger from the 1928-34 era in a street roadster there. He broke a lot of parts along the way but inched his own record up year after year. 120 MPH isn't fast in absolute terms but doing it the way my friend Norm Adams did it can be appreciated by any antique car person.https://www.gazettes.com/sports/fea...118769a-1160-11e3-b0f5-001a4bcf887a.html