"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
If it is a GMC you need to get it away from your Chevy engines before they die of embarrassment. I'll volunteer to drag it away, no charge.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
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.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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 bet Panic is right about the Howard heads having paired intake ports. So What head is shown in the original, non-paired intake, picture?
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
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?
Looks like the nuts are already off the manifold studs. Pull the manifold and look for "Howard" between the #2 and #3 intake ports.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/13 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
1970 Chevrolet C10 - Grandpa’s- My first truck.—in progress to shiny 1972 Chevrolet C20- Rusty- the puzzle box lid for the C10. 1950 Chevrolet 1300- in progress to shiny. 1962 AMC Rambler American- my wife’s
Parts trucks- 1951 GMC 9300 1951-GMC 9430 1951- Chevrolet 1300
What electronics are you going to use to control it?
Edit Deux: Is this the 302 you mentioned in your other post?
Yes, they are injectors.
Today I was looking at the MS3Pro. It looks rather friendly, but I'm undecided at the moment. I'm still working on getting all the mechanicals in order, verifying firing order by cam, mostly just seeing what I got! I kinda don't want to disassemble anything, but I'd love to see if the roller cam has any markings. I'm short some push rods and need to plumb the rockers through the head. I also need to plumb the remote filter. I need to make sure that everything that is supposed to get oil, does. Kinda reverse engineer what's been done to this thing.
You know, the never ending "to do" list.
This is the 302 that I was figuring out what I needed for a bellhousing in my other post. I might have that part a little figured out. Still working on it.
The MS3Pro appears to have a good set of features on paper, but I have never been impressed with any of the megasquirt products I have used.
Have you looked at the Haltech units? Depending on what features you want, it might be a better option for you.
Do you know what you want to do for ignition? The Haltech supports drive-by-wire where the MS3Pro doesn't, but with what you have there going cable throttle probably makes more sense.
The Haltech can control a 4L60e and a few other transmissions if you decide on a modern automatic. The Haltech also supports closed loop automatic tuning. Whether that is a bonus or not depends on you.
I saw your post in the youtube thread about sensors, but it seems more applicable to this thread so I will comment here.
You asked about measuring airflow on this engine. You would really need some kind of MAF per cylinder to do that. I will see if I can find a small one that would fit, but it would take some custom work.
I suspect that you are going to have to run this in speed density mode though. Not knowing the cam specs will make tuning that harder, but it is doable.
Depending on the ECU you go with, you will probably need MAP (manifold air pressure) and IAT (intake air temperature) sensors.
Curious how that would work with 6 separate manifolds.
I'm curious about the valve layout. On my 12 port crossflow head the intake and exhaust valves alternate. Are yours grouped and can you run a stock cam configuration?
Guessing by the 2-2-2 intake ports, it uses the original GMC (and stovebolt, and some other older L6 engines) lobe positions. You can use any cam made for the original head, but given the 12 port advantages the available grinds may not be suitable: Ex - In - In - Ex - Ex - In - In - Ex - Ex - In - In - Ex
You could do the LS thing and mount the coils to the valve cover bolts.
Or potentially move the filter to the frame and build a bracket to go along that side of the engine to hold them below the fuel rail. The early and late (99-02 vs 03-06) Gen III LS engines had different length plug wires so you couod pick the length you liked and use off the shelf parts.
Are you planning to use LS coils or something else?
If your like me you really enjoy making stuff. I don't have anything fancy. I bought a medium sized Grizzly mill about 5 years ago and a PM 12x36 lathe a couple of years ago. I don't have any schooling in machining but I take it easy and get by. No major crashes yet. I have been avoiding dealing with my thermostat mounting issue. Thanks for the post.
No schooling in this for me, neither. But the more I do, with an attitude of "Why can't I do this stuff!", the more I learn. Which just goes to show, it's never too late! And not just limited to machining. I think I picked up enough supplies to try some more advanced upholstery on my Model A Roadster seat springs. And why not! If some guy in a small shack let's you drop off your springs in the hope that, when you pick them up, they will look like what you envisioned. He might be faster because of a lifetime of experience, but it doesn't mean I can't figure it out and do the same. Everything on our Stovebolts was touched by some human in a factory and turned in to the trucks we love. Ain't nothing mysterious or magical about it. Just some dude (or chick) that did what they were taught to do. And between Youtube and The Stovebolt and other internet information, it's even easier to get that training and build on the pioneers. And if we make a mistake, we start over and try not to repeat that mistake!
Short answer! Yeah, I like making stuff! Best part of the day is when I can say, yeah, I made that! Even if, sometimes, I'm only talking to myself!
BTW, more stuff. Next up, bolt holes to fasten it all together. The trigger wheel might have to wait until I can get some basic clocking. So, I might start on the sensor bracket.
I bought a V pulley with the center I needed and turned it down. I need to be able to change my blower pulley without moving the crank trigger. I'm looking forward to how you mount your sensor.
The timing cover is one of those racing types that have a removable cover over the cam gear, in case you want to drive, say, a Enderle Nitromethane fuel pump. I plan to use that to my advantage and use the mounting points for a sensor bracket, between/inside the V-belt.
The picture shows a large plate timing cover with a candlestick attached and the Enderle attached after that. I'll get pictures of my stuff later.
I didn't think about mounting it on the cover. That would keep it away from my 250 amp alternator. I'll have to see how that works with my dry sump pump on that side. Thanks for a new perspective.
