Camshafts 1955 and 1956

[Robert D.]

I was wondering what camshaft was used in the 1955 Corvette. Were they all solid lifter? Were the 1956 Corvettes all solid lifter also, or was it just the GU engine code? What cam was used for the GU code? Was it the Duntov cam? Thanks in advance for your help.
Bob

[Joe L.]

Re: Camshafts 1955 and 1956

I was wondering what camshaft was used in the 1955 Corvette. Were they all solid lifter? Were the 1956 Corvettes all solid lifter also, or was it just the GU engine code? What cam was used for the GU code? Was it the Duntov cam? Thanks in advance for your help.
Bob

Bob------


All 1955 and 56 Corvettes used a mechanical (solid) lifter-type camshaft. The "Duntov" cam was not used for either of these years; it was introduced for the 1957 model year in Corvettes.

[John N.]

Re: Camshafts 1955 and 1956

Joe
I have always believed that the 077 1956 GU camshaft was a Duntov camshaft and if anything was a slightly higher performing cam than the 1957 097 cam. Duntov tested the cam at Mesa AZ in late 1955 and its purpose was to inable the Corvette to excede 150MPH at Daytona Beach in the sand. (also NASCAR, Sebring and later customer use). Ken Kayser also refers to the 077 as a Duntov cam on page 108 of his book. At my age I always stand to be corrected. Thanks for your consideration and the great service you provide to the hobby.
Regards

Just received a phone call from Ken and he said that the 077 and 097 cams per blueprints are identical except that the 077 has a oiling slot on the back journal. Thanks

[Stuart F.]

Re: Camshafts 1955 and 1956

I can confirm what John has said. I bought and installed many 077 cams back in the day, and their specs mirror the 097 with the exception of the oil slot. I cut my teeth on 265's.

Stu Fox

[Roy B.]

Re: Camshafts 1955 and 1956

55 56 cam 265 engine trivia
left solid=Corvette
right Hydraulic=car

[Stuart F.]

Re: Camshafts 1955 and 1956

Roy;

What about the early 55 cars with solids?

Stu Fox

[Roy B.]

Re: Camshafts 1955 and 1956

I don't know much about the cars ,just mentioning the differences

[John H.]

Re: Camshafts 1955 and 1956

Just received a phone call from Ken and he said that the 077 and 097 cams per blueprints are identical except that the 077 has a oiling slot on the back journal. Thanks

That's interesting - the published specs for the 077 and 097 differ in the Colvin CBTN book; the 077 shows .404"/.413" intake/exhaust lift, and the 097 shows .394"/.400" (duration same for both cams). The 077 and 097 also show different casting numbers for the core (3734078 for the 077, 3736098 for the 097).

[Duke W.]

Re: Camshafts 1955 and 1956

It's always been my understanding that the 077 cam/pin assembly had the exact same lobes and indexing as the 097. I think the reason for the different cores is that the "notch" in the 078 finished camshaft was formed by the casting process, so a new core was needed for the non-notched camshaft, and it carried the number of the notchless finished '57-up Duntov camshaft.

(As I've stated many times before, the cast in number is the drawing number of the finished camshaft and was cast in to ID the cam. Technically, there was no "core number", but the finished camshaft number was cast in to serve as an identification number since each Chevrolet cam was machined from a specific cast core.)

I may have mentioned this in the past, but I came across an 077 camshaft in an opened tube that, according to the story of the person who owned it, was acquired as part of a dealer's going-out-of-business sale. The part tag on the tube is faded but I can make out the Group No. (519) and part number (3744077).

The area that usually has the cast in finished camshaft number is ground down and "078" is hand stamped. It has the rear journal notch, clearly cast in, not machined. The nose has a blotch of blue and green paint. The rear face of the no. 5 journal has green and yellow paint blotches. There is green paint around the circumference of the area between the first and second lobes from the front and the distributor gear and no. 5 journal. I believe these color blotches either ID the cam, or are inspection marks, or maybe both.

Now it gets interesting. I personally watched this cam being run on a lobe analyser, and the data correspondes to the 3896930/29 '67-up hydraulic lifter 300 HP camshaft!

The cam still has the Parkerizing on the lobes and has clearly never been run in an engine.

If anyone can sort out this mystery, let us know.

Duke

[John N.]

Re: Camshafts 1955 and 1956

Duke
I have a simular 265 mystery. When I purchased the 56 Sebring car from Frank Buck he threw in a NOS 265 Flint short block assembly. Dick Robinson pointed out that the block casting numbers were the wrong size. The casting date was the equivalent of December 19_6. Turns out it was 12/1966. The china walls were of the 66 configeration. The camshaft was notched but carried the 57 up hydraulic cast number. The timing chain cover had provision for two sizes of dampner, ie break off the tab not needed. Pad was unstamped. Possibly a military or other item.
Regards

[Duke W.]

Re: Camshafts 1955 and 1956

I took another look at this cam (It's in my posession now,), and on closer inspection it could be that the notch was machined out by a relatively crude circular tool. The bottom of the notch is not flat, but has a slight concave radius.

If the lobes were actually the Duntov profile then I could believe that this cam was made as a service part after the original supply of '56 notched cores was exhausted, the notch was gouged out from the 098 blank, and the original ID number was ground off and hand stamped 078. Chevrolet sold a lot of these cams over the counter, and it could be that there was still sufficient demand to manufactur them well into the sixties, since there were still a lot of 265 running around that guys wanted to hot rod.

A similar situation occured with the BB SHP cam. The drawing for the ...144 cam says it can be made from the ...366 blank as long as the groove is machined to the ...144 drawing specs. The 144 blank had the groove cast in.

But the lobes are not Duntov, so the above plausible scenario goes out the window. Stange things that are inexplicable sometimes occur. The block you referred to seems pretty mysterious, too.

Duke

[Robert D.]

Re: Camshafts 1955 and 1956

Thanks for the information everyone.

Bob