Technical Thomas magnesium rocker arms

I've found set of 16 Thomas magnesium shaft mount rocker arms. They have CV 8 embossed on the side of each rocker arm. Can anyone tell me what these fit?

Thanks,
Rex

 

Cadillac V8? Just a guess but they did make them for Cadillac and Oldsmobile.

 

how many in the set? olds had a O before the number, or at least the ones i have seen. and the set for a caddy i saw had just a C before the number. they did make them for chevy 6. i have never seen them but maybe that explains the CV?

 

Her's a pic of them...........................they look like FE Ford or Olds stuff to me, but the guy says they're for a SB Chevy.

 

SB chevy is what I was thinking. Whats the shaft diameter?

 

Are there oil passages in the 'stands' where they bolt down? That one end looks open, is there a plug inside it past the cotter key?

 

Is the open end of the shaft tapped?

 

can you get a better picture of the rocker shaft stands?

 

Seems that my rockers that I sold had OL8 on the side and they were for an Olds??????

 

Mine too. they arent olds.

 

Sure looks like Caddy to me. High jacked this picture from another thread here on the HAMB. Says in the thread that they are marked c-8.
http://www.jalopyjournal.com/forum/threads/cadillac-adjustable-rockers.773444/

 

More pics...........................

How can these possibly fit a SB Chevy head based on how the stand mounts ?

 

all the pics I have seen so far of the chevy ones show oiling through the end of the shaft with a tube that taps into a hole drilled into the lifter oil galley, and the stands dont look anything like these, they dont have a through-bolt. Let me check some later photos, most of the ones I am looking at are '55/'56. If they DO turn out to be chevy, I am DEFINITELY interested. Definitely not olds or cad, I knew that right away.
Heres a 1955 Thomas ad, the stands look different. maybe they changed the design of the stand later? That CV-8 yells chevy...

 

Whats the center-center distance on the stand bolts?

 

That and the oiling is whats bugging me. The ones I have looked at in the past, the stands are flanged under the shaft, the stock rocker bosses are machined flat, studs screwed in with sealer on them, and a nut and washer holds them down. Ollie Morris had them on the sbc that replaced the flathead in his RED.
I will try to find some circa 1959-1961 photos, and see if they changed to a through bolt rocker stand later on.
And no, this stuff doesnt just "bolt on', even the early versions I am looking at required some pretty extensive machine work.

 

I do not currently own these but am considering buying them, ONLY IF they are for a SB Chevy. Therefore, I can't answer any specific questions, sorry about that. The seller wants a LOT of $$$$ for them. My intentions are to install them on 1960 aluminum heads on a magnesium small block that ran at Indy.

 

Found several pics of the shaft rocker set-up on Howard Johansons '55 chevy from early '56, they have a through-bolt stand with a central bolt similar to these, unfortunately the photo is a pdf, just trying to figure out how I can change them to a jpeg and post them.
Thing is, they are oiled as I outlined above, these dont appear to be oiled that way.
Be aware, these are NOT a simple bolt-on, extensive machine work is involved.

 

If you decide to pass on these, please contact me I would be interested, depending on just how much "A LOT of $$$$" is.

 

Is it too late to change my answer?
After seeing those other pictures and that ad I'm going with George on this one.

George. It's very possible that they oil the body through the push rod. I know the new shaft mount stuff I deal with does. You would have to pull one apart to know for sure though.

 

I did notice an oil hole in the adjuster, that thought had crossed my mind.

I printed the PDF, then scanned it, sorry, I am a computer hack.
Check this out. Are these stands held down with a longer head bolt, like an early hemi? You can see clearly how this particular set was oiled, but you can bet these ones were real early, this was published in early '56.

Should add here, note the mushroom tappet in the top right photo. This was one trick 265 for 1955.

 

I had wondered if they could possibly use a headbolt to mount the stand...............................

 

There's only problem with that. The head bolt hole is offset. In the picture from 56 it looks like they've offset bolt in the stand to keep the shaft in the stock position.



On the other set the bolt looks centered on the shaft. Which means if it used the head bolt hole the rockers would be too low for the pushrod.



Correct me if I'm wrong there. I'm just brainstorming.

 

That bottom pic is of a Cadillac head..........................isn't it ?

 

Should be the first picture you posted of the rockers. Or at least that's what it was supposed to be. Did I mess that up?

 

You mean this?

^^^Thats a chevy head. The caption says they are using cadillac bolts.

 

Heres the set-up on Ollie Morris' dragster, its the one I described earlier with flanges on the bottom of the shaft supports and studs into the original rocker stud holes, and you can see the 90 deg. oil fitting in the end of the rocker shaft. This looks to be the same deal as in the ad, and it looks like this version bolts up with no machine work! This is later than the Howard Johanson deal, late '56.

The text describes the cam as "an experimental Potvin with .450 lift". That was a MONSTER lift number for a sbc in 1956.

 

OK....................now I understand. Thanks for pointing that out.

 

OK................................that helps.

Thanks,
Rex

 

In the beginning both Thomas and Gotha offered adjustable rocker arms for Oldsmobile and Cadillac engines because those engines were not offered with a solid lifter cam (that I remember) ....thus no adjustable rockers available from the dealer parts counter for aftermarket solid lifter cams. I don't believe they sold nearly as many Chevy kits because their unique stamped steel rockers were adjustable and reliable for any street application.

 

Thats my guess as well, (IIRC, Olds did make adjustable rockers for the so-called "export" solid lifter J-2's) I think the vintage Thomas shaft mount chevy set-ups are really rare, this is actually the first time I have seen current pics of one. They were also BIG $$ by 1950's standards.