1967 427/435 Cam and Lifters

[Joe R.]

Re: 1967 427/435 Cam and Lifters

Jeff,

I remembered that I had posted a camshaft sheet on a nearby thread called "Correct Cam." There are two with that title. Anyhow, it lists 3904366 as the GM part number for your cam. I don't know for sure that the number is correct, 67 is a bit out of my league. But it seems to make sense, because using the NAPAonline interchange with that number, it comes up with the following result:

http://www.napaonline.com/NOLPPSE/(S(pd13ar45krptk445pifem545))/Results.aspx?Ntt=3904366&Ntk=Interchange%20Number& N=0&Nty=1&D=3904366&Dn=0&Dk=1&Dp=3

I reread your original post. I got the impression you are doing a complete rebuild of the engine. I would recommend searching the archives on tips for working with the machine shop before having any machine work done to the block. Specifically, assuming you have an original, numbers matching block, don't let them deck the right (passenger side) of the block. That'll wipe out your broach marks and numbers. Also, make sure you use the second design valve springs. The first design is prone to breakage. I'm sure you don't wanna drop a valve in your "new" engine! The GM part number is 3970627. Here's a good thread on valve springs:

https://www.forums.ncrs.org/showthread.php?t=53851&highlight=3970627&uid=7546

Joe

[Joe R.]

Re: 1967 427/435 Cam and Lifters

Jeff,

Here's some more wisdom I culled from this board. It covers a variety of topics. Most of it is from Duke, Joe L., Clem and Mike H:

Use OE or OE equivalent parts throughout with one exception. The one area where I recommend true racing parts would be the connecting rods. A set of Crower Sportsman rods will make for a bulletproof bottom end. (This may not be the most current recommendation, search the archives.)


Sealed Power and Clevite offer 627 clones that you can probably buy at lower cost and they most likely manufacture the part sold by GM. The prior production spring was single with a damper and prone to failure.


Use 3947880 valve keys as they are better material than the originals. You want to use the 3947880 keys with the 627 spring kit. Heavy BBC valves pulled right through the original design keeper. 880s are hardened so to find which you have on your BBC use a file. GM colored coded the hardened ones for both SBC and BBC and the color that sticks in my mind, was purple and green. With the parts system they did not need the colors anymore. I would still use the "file" test to make sure you got the hardened ones.

Purple and green were, indeed, the color codes for, respectively, the small block and big block valve locks. However, that color coding seems to have mostly "gone by the wayside" some time ago. In the last several years I've noted both of these part numbers as being of plain finish or copper plated.

Replace the timing set. Your original used a nylon-tooth cam sprocket. Even with low miles, this will be deteriorated by now. Does the L-71 use the nylon tooth part?


Shims - Use GM #3875916 (0.015" thick hardened shims).


How do you intend to use the engine? Will it be raced or run hard? Can you provide a parts list of everything you plan to use in the engine?


Joe

[Thomas N.]

Re: 1967 427/435 Cam and Lifters

Hi:
If you do not have a NAPA around or do not get a discount from your local NAPA dealer, you can get the Federal Mogul CS-165R camshaft from Northern Auto Parts. They are a good mail order house. I am in no way affiliated with them. I've received good parts priced right and shipped right out. The link to the CS-165R from them is as follows:

http://www.northernautoparts.com/ProductModelDetail.cfm?ProductModelId=15040

[Duke W.]

Re: 1967 427/435 Cam and Lifters

Jeff,


Sealed Power and Clevite offer 627 clones that you can probably buy at lower cost and they most likely manufacture the part sold by GM. The prior production spring was single with a damper and prone to failure.

Do you have the Sealed Power and Clevite numbers? I've never been able to cross reference the second design dual spring.

Duke

[Jeff M.]

Re: 1967 427/435 Cam and Lifters

Joe, Duke, John, Thomas - Thanks for all of the extra effort to provide me with all of the info. I really appreciate all of it, since I am new to the NCRS, I am still learning alot about my car and the best parts to use to correctly restore it. Thanks again, Jeff

[Joe R.]

Re: 1967 427/435 Cam and Lifters

Do you have the Sealed Power and Clevite numbers? I've never been able to cross reference the second design dual spring.

Duke

Duke,

I wasn't able to cross reference GM # 3970627 directly using NAPAonline's interchange. However, I selected a vehicle of 66 Corvette 427 and it came up with two Sealed Power dual valve springs:

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS1581&Description=Valve+Spring

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS708&Description=Valve+Spring

What is the damper?

Joe

[John H.]

Re: 1967 427/435 Cam and Lifters

Duke,

I wasn't able to cross reference GM # 3970627 directly using NAPAonline's interchange. However, I selected a vehicle of 66 Corvette 427 and it came up with two Sealed Power dual valve springs:

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS1581&Description=Valve+Spring

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS708&Description=Valve+Spring

I suspect the first one is equivalent to the 3970627. What is the damper?

Joe

Joe -

The photo of the 1581 (top link) shows the flat damper, counter-wound between the inner and outer spring; the other one (bottom link) doesn't show a damper.

[Joe R.]

Re: 1967 427/435 Cam and Lifters

John,

Thanks for the info!

Joe

[Joe L.]

Re: 1967 427/435 Cam and Lifters

Jeff,

Duke is cautioning you to avoid Comp Cams because they don't Parkerize their cams. Check out this thread:

https://www.forums.ncrs.org/showthread.php?t=66214&highlight=parkerize&uid=7321

My 66 L-72 (427/425) was recently rebuilt. Right now it has the Comp Cams camshaft that Joe Lucia mentioned. But I plan to swap it out with the Federal Mogul part in this thread:

https://www.forums.ncrs.org/showthread.php?t=67038&uid=5648

Joe

Joe------


I don't think I'd advise doing that. Comp Cams makes very high quality products. They have been in the cam manufacturing business for a long time and there are tens of thousands of their cams out there. I have never heard of a problem with a single one, including the 65-71 SHP solid lifter big block cam.

While their cams are not parkerized, that does not mean that they don't use some other process to produce the same results. I have every confidence in their products. In fact, I consider them equal to Crane and Crower.

Some of the best cams on the market are made by Iskandarian (even to this day). I don't think I recall any of their cams being parkerized, either.

[Duke W.]

Re: 1967 427/435 Cam and Lifters

The Internet is full of stories about Comp Cams "wiped cam lobes", especially the XE series. Parkerizing is a definite aid to successful cam breakin. Otherwise GM would not have done it.

If I can get a Parkerized cam that is my first choice. Federal Mogul and Crane both Parkerize their cams, so they are my first choices, but we'll have to wait and see if Crane comes back with the same products and processes.

In the meantime, Federal Mogul or Dana (Clevite) are my only vendor recommendations for OE replacement cams.

It's not clear to me if either the VS708 or VS1581 spring is equivalent to the GM ...627. The GM spring is dual with no damper and the retainer and valve seal are integral. Though the specs say the VS 1581 is a dual spring with a damper, I don't see the damper in either photo, but the parts shown in the photos are not always the exact part - just a part that is representative.

My recommendation is still to use the ...627 GM spring for all big block rebuilds (along with the proper OE replacement cam) - until clear evidence that an exact equivalent is available in an aftermarket OE replacement product line.

Duke

[Joe L.]

Re: 1967 427/435 Cam and Lifters

The Internet is full of stories about Comp Cams "wiped cam lobes", especially the XE series. Parkerizing is a definite aid to successful cam breakin. Otherwise GM would not have done it.

Duke

Duke-----


I am unaware of this. I do know that Comp Cams has been selling cams for a lot of years and if they regularly failed, I expect they would have gone out of business a long time ago. I would more expect that failures of their cams resulted from improper break-in. In that regard, do we know that Federal-Mogul cams experience no or few failures compared to Comp Cams? In fact, it seems like I just saw recently on this board a report of someone having a failure of a Federal-Mogul cam.

I agree that GM would not have done the parkerizing if it was not necessary. However, as I mentioned, other cam manufacturers might use some other process or technology to achieve the same purpose. In any event, thousands of non-parkerized cams of many manufacturers have been installed and run without problems.

As far as the valve springs go, when I find that a non-GM replacement for the GM #3970627 valve spring unit appears absolutely IDENTICAL to the GM-sourced part, I'll believe that the 2 are the same. If they are the same, they will appear absolutely IDENTICAL. I'll bet I NEVER see that.

Now, if they appear different, this does not mean that a non-GM replacement for the GM #3970627 is functionally inferior, less durable, or otherwise less desirable than the GM piece. It might even be better. But, if does not appear absolutely IDENTICAL in every way, it's NOT the same piece.

[Duke W.]

Re: 1967 427/435 Cam and Lifters

The reports of Comp Cam failures are more likely to be seen on other Corvette boards where guys are more prone to install "hot rod" rather than OE replacment cams, so such reports here are rare.

I agree on the valvespring issue. If it doesn't look exactly like the ...627 spring, then it's probably not the same part. That's why I continue to recommend the ...627 for all BB rebuilds even though they may be more expensive than aftermarket springs.

They have proven reliable from the time they went into production circa '69-'70 and are a vast improvement over the original single spring/damper design, which had a high failure rate.

Duke

[Joe R.]

Re: 1967 427/435 Cam and Lifters

Joe------


I don't think I'd advise doing that. Comp Cams makes very high quality products. They have been in the cam manufacturing business for a long time and there are tens of thousands of their cams out there. I have never heard of a problem with a single one, including the 65-71 SHP solid lifter big block cam.

While their cams are not parkerized, that does not mean that they don't use some other process to produce the same results. I have every confidence in their products. In fact, I consider them equal to Crane and Crower.

Some of the best cams on the market are made by Iskandarian (even to this day). I don't think I recall any of their cams being parkerized, either.

Joe,

A man has got to know his limitations. Since I am just a lowly EE and this is my first time rebuilding an engine, I have to be very careful. The Comp Cams camshaft probably is just fine. But the Federal-Mogul cam seems a safer bet to me for three reasons. One is the Parkerizing issue that has already been discussed. The second reason is that you guys are my safety net. I get the most help from this web site if I stick with OE or OE equivalent parts. The third one is the break in is more elaborate with the Comp Cams camshaft. They want you to break it in using just the outer portion of the valve spring. After that you install the inner spring as well. It sounds like this isn't necessary with the F-M cam.

Are you implying that the cam being discussed here is applicable to all 65-71 SHP solid lifter engines?

Joe

[Rich P.]

Re: 1967 427/435 Cam and Lifters

Don't know if this info can help anyone here but these guys on the Yenko board have had the original 143 cam made. here is the order info.

In the first post you can click on the red highlighted text for another thread

Rich

http://www.yenko.net/ubbthreads/showflat.php?Cat=0&Board=UBB10&Number=420576&page=1&fpart=all

[Joe R.]

Re: 1967 427/435 Cam and Lifters

Duke,

I wasn't able to cross reference GM # 3970627 directly using NAPAonline's interchange. However, I selected a vehicle of 66 Corvette 427 and it came up with two Sealed Power dual valve springs:

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS1581&Description=Valve+Spring

http://www.napaonline.com/MasterPages/NOLMaster.aspx?PageId=470&LineCode=SEP&PartNumber=VS708&Description=Valve+Spring

What is the damper?

Joe

Since I have some lying around waiting to be installed, I took some pictures of the GM 3970627 springs for comparison.

Joe