Here is what you are contending with as far as cylinder wall thickness. Of course YOUR BLOCK MAY VARY-- and if you hit water------- Herb
Herb, Two really useful photos there; thanks for posting. I feel much more confident of boring up for 261 Chevy pistons now. Do you have any photos of a '28 head sectioned? It would be good to know how much work I could do on the inlet valve throat 'short side radius' which looks like the biggest restriction in those ports.
Stueee No, I wish I had a 28 head that was otherwise unusable. I always wanted to do a comparison of a three port, and a '28 head on a flow bench. Never got around to making a simplified bench, and the call of the dollar let my last 3 port escape---so that's for someone younger who want's to take on a project---I would certainly be interested to know, My gut feeling is that there isn't much difference if you are talking about a street engine. I have a factory picture, in a reprinted service bulletin, that shows the difference between a '27 and a '28 head, both sectioned. Let me find it and see if I can copy it. Might help a little. Herb
Interesting that non genuine single port heads were being made. This is from Chevrolet Service News September 1928.
Drat! that's the pix I remember, and it's obviously the wrong subject! My CRAFT acting up again. (can't remember a ******* thing) Thank you Kume, for saving an old man from digging into his dusty archives. And my apologies to other's who were waiting breathlessly. Humble Herb
Yes, buy genuine Chevrolet where our heads crack and keep you coming back for more, don't buy those junk aftermarket heads
Haha. yes and looking at those cross sections you have go to wonder why they abandoned the three port so early.
This is an idea of how the Olds head looks with a BBC valve cover. The adapter plate will attach to the head with countersunk 8-32 screws. The plate is drilled and tapped 14/20 for the cover to bolt on. I will make a two piece side cover. The top will reach the aluminum plate and the exhaust will pass through it. If I step up I will get a thick enough piece to cut fins on the lower plate which will have a lip that helps clamp the upper cover plate
Rich, That looks good. Here are some shots of the Fronty repo I got and a GMC I cut down. The GMC fits and looks better I think but I didn't spend enough time fitting before welding. I might try another one. They are thin and not nearly as straight as they look. The indents on the Fronty get in the way but it could work.
The rocker assemblies were with the engine when I bought it. They fit the bolt holes in the Olds head. I just assumed they were stock Olds rockers.The BBC valve cover is an aftermarket, cheap, stamping. But pretty sturdy. And I had it screwed to that plate for welding. I intend to incorporate a spray bar either inside the cover or maybe on top, to oil the rockers,
Probably just the camera angle. They don't look quite as spindly as original ones Sent to me out of interest. Not mine and not a hot rod but right at home in this thread. Original Chevrolet
The rocker shaft on the Olds head is 13/16. The Chevy head i have here has a 17/32 dia. Shaft. So, yes it is quite a bit sturdier.
Still fooling with the Olds head on the Chevy. It looks like I will use the Chevy pushrods. Which have the copper socket on top. But I am missing one socket. Anyone here want to sell one or know of a source?
Well I don't know. But I'll find out. Thanks for the info, OK. I looked up Billy Possum from the links I found. Lots of Possum traps. And cook books. How do I find the Chevy parts?
Rocker mystery: As per a suggestion much earlier in this thread, I decided to use Chevy Stovebolt 216 rockers on my 28 head. I bought some rockers at last year's fall Hershey show from a vendor who had a lot of 216 parts, but there weren't enough "straight" rockers there to make up a set of 8 for my 4 banger. Stovebolt parts are not especially common here in the UK, so I was lucky to be given a complete but frozen 216 motor that came out of a '49 pickup. However, while these rockers have the same shaft diameter and the same ratio, they're not the same; they're quite a bit lighter -see the picture below. Are the two bottom rockers different versions? Just wondering whether the factory upgraded from the middle rocker to the bottom one, or whether I actually bought something different (maybe 235 rockers?) at Hershey.
Stueeee, Looks like the bottom one is 235/261? I'd use those if you can find them- the early 4 and 216 designs tend to "bend up" after time, where the 235 rocker has that nice reinforcement.
Got it covered. Thanks.Now I wish I had adjusters with 3/8-24 threasd and a 3/8 ball to fit the Olds rockers. The Chevy adjusters I have are 7/16-20 thread.with a .470 ball. But I can tap the Olds rockers for the Chevy adjusters.
The idea is to use the Stovebolt rockers as an upgrade, they have the same ratio as the 4 banger ones, but have more metal in them. I am in the process of warming over (rather than properly hotting up) a motor for my 28. The "new" rockers will be working with a set of BB Olds valves in the '28 head.
Do you have pictures of the BB Olds valves in the '28 head? Or did you already post that and I forgot?
I'm dropping a more modern engine into my 26 Touring, I have a 28 engine and multiple parts I wouldn't mind liquidating..... central Indiana. Engine is still in the car, I think a couple extra heads.....
In the end i decided against the rockers shown in post 1958, above. Went back with stock rockers but had to make stands for the Olds head. Now I need to drill and tap the head for the stands and plug the old holes. So if anyone wants the other rockers and shafts, contact me.
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