First thing you need to do is share with us what you used to paint the block so that everyone will know what the correct color a stock AD Chevrolet truck engine is supposed to look like (even though this is neither stock, nor Chevrolet).
Does anyone know what company built this head? The 45 degree input ports rule out most 12 port GMC head builders. I know that the Fisher heads had 90 degree intake ports. Plus, all of Horning's heads were cast iron. The head in Mark's picture at the top of this thread looks aluminum to me.
The two piece valve cover looks like a Bill Fisher part, but the only one I've ever seen had "Fisher - GMC" cast into the top.
So, you fellas got me looking into it a bit. Yep, Howard Johansen/Nick Arias head, cover and rockers. Schultz intake. Schultz ignition trigger. Looks like Schultz machined the valve cover smooth. And it wouldn't surprise me if he had Donnie Johansen grind the cam to his specs. From what I understand, these heads were made for the 302, but from what I was looking at, alternator mount, etc., this block looks like a 270? You guys let me know/chime in. Still would be a fun project to have.
Below is info on the Johansen head copied from "The 12 Port Story Pt. 6" written by Herbert Hall (originally printed in Vol. 2, Issue 1 of the 12 Port News)
By the late Fall of 1951, about 3 to 4 months after that day Art was down to see Howard about the Bonneville car, Howard Johansen had gone ahead and produced just such a cylinder head; like the one they had talked about that afternoon. In producing his first 12 Port head for the GMC, Howard Johansen chose 356 aluminum. He not only patterned his combustion chamber after Harry Warner's GMC head, but also after the earlier, flat chamber of the 1928 Chevy four. Howard also decided he was right concerning the intake ports. On his 12 port head, he inclined the intakes to about 45 degrees for better flow, straight down to the valves. In doing this, he was looking back to the intake design of the Riley 4, and engine Howard has successfully campaigned around the country with Jim Rathman at the wheel in a car owned by Andy Linden.
The new Howard 12 port head for the GMC had 1 7/8" intake valves and 1 3/4" exhausts. The intake ports were 1 7/8" x 1 11/16" and the exhaust ports were 1 19/32" x 1 28/32". The head had bronze valve inserts and bronze valve guides. A stock GMC rocker arm assembly was used and Howard reground a stock steel cam for the head. With a Howard F series cam, these Jimmies revved into the 5,000 to 5.500 r.p.m. range and up to 6,500 r.p.m with a Howard M series cam. Howard also had special tubular pushrods available for the GMC. In April of 1952, "Hot Rod" magazine ran Howard's first ad for the new 12 port head for GMC. Art Benjamin, who was often over to Howard's shop and who was a distributor of Howard cams and speed equipment, recalls that there were from 10-12 of these heads produced, all in aluminum. This conflicts somewhat with other estimates of around half dozen heads produced, but Art is very confident in his estimate.
The dyno tests proved out Howard Johansen's thinking on the design changes he envisioned after looking over the Wayne 12 port that summer afternoon. In an advertisement for "Howard's Racing Cams," h.p. levels of 303 h.p. from a 297 cu. in. GMC with the Howard 12 port head and using straight methanol were obtained. When the fuel was beefed up with the addition of 25% nitro, the h.p. jumped to 351, that's right, over 350 h.p. form a 297 cu. in engine. I have in my files copy of a Howard GMC engine testing report, in which a 298 cu.in GMC fitted with a Howard 5 carb manifold, Howard F-7 cam, 12:1 compression and Howard pistons, running methanol and of course the Howard 12 port head, turned out a top h.p. rating of 355 h.p. at 5,200 r.p.m., and amazing figure. These 12 port cylinder heads were first offered at $270, and later were raised to $290. What deal, that was a very low price even in 1952.
I found this, shall we say, interesting quote from Dan Warner (son of Harry): "Don Ferguson III had the 300 MPH exit speed at Speedweek last year. He was using an original Wayne head." I hope that's a typo or bad memory, we all know why.
I've poked around, and can't find any 12 port head with 45° angled intake ports and evenly-spaced individual ports as shown. All of them had paired ports, like SBC, BBM, etc.
I've poked around, and can't find any 12 port head with 45° angled intake ports and evenly-spaced individual ports as shown. All of them had paired ports, like SBC, BBM, etc.
They are paired. "Schultz intake." He made a manifold for individual throttlebodies. KMS throttlebodies, if I looked it up correctly.
I've poked around, and can't find any 12 port head with 45° angled intake ports and evenly-spaced individual ports as shown. All of them had paired ports, like SBC, BBM, etc.
These links show some "Howard" heads that have paired ports as you said. One picture in the 1st link shows "Howard" cast into the head. "Howard" is Howard Johansen of Howard Cams fame.
I'll get ya'll a better picture. Gonna take a minute or two. Got an after lunch meeting, managers roaming through the place, roll up door vendors fixing broken doors, employees that need direction, ..........
The distance between adjacent throttle bodies in your picture is the same all down the head. So each pair of throttle bodies *1+2, etc.) have a "Y" shaped manifold to conform to the 2-2-2 intake ports?
