L-68/36 cam for 67

[Tim S.]

Can anyone recommend a replacement cam for the 67 L-36/68 engine?
Thank You

[Joel F.]

Re: L-68/36 cam for 67

Tim,

I believe Crane CRN-969391 is the L36/L68 cam. The Crane grind number is 3883986, which is the same as the GM part number. I am sure Federal Mogul and the others have versions of the same as well.

[Joe C.]

Re: L-68/36 cam for 67

http://www.flatlanderracing.com/musclecams.html

L36 camshaft 3883986.

[Duke W.]

Re: L-68/36 cam for 67

I expect that Dana and Federal Mogul offer it since they offer just about all the OE cams ever made.

You can start by looking it up on the NAPA site, which will get you the Clevite (Dana) number.

For your '67 you need the version with no rear bearing goove in conjunction with the single oil feed hole rear cam bearing.

Duke

[Joe L.]

Re: L-68/36 cam for 67

Can anyone recommend a replacement cam for the 67 L-36/68 engine?
Thank You

Tim-----

GM #12364055. This is a Crane-manufactured "clone" of the cam you seek which includes lifters. You should be able to get one for less than $200.

[Joel F.]

Re: L-68/36 cam for 67

Tim-----

GM #12364055. This is a Crane-manufactured "clone" of the cam you seek which includes lifters. You should be able to get one for less than $200.

That's about the same price as Summit has the CRN-969391 with lifters.

[Joe C.]

Re: L-68/36 cam for 67

Can anyone recommend a replacement cam for the 67 L-36/68 engine?
Thank You

Tim,

I recommend the FM part, if it exists. It would be a pleasure to help you, but I don't have A FM catalog handy.
FM lives in the stone ages, because they have a fu%$#@-up website. I always try to look up their parts online, in the vain hope that they'll eventually include an online parts listing. No dice.
FM does reproduce most of the popular SBC camshafts, as does GMPP. They probably do the same with BBC, but can't find online.

Joe

[Tim S.]

Re: L-68/36 cam for 67

Duke Thank you for the information and I have a further question on your comment about single hole cam bearings and no camshaft rear groove. When did Chevy utilize the rear groove cam's, was it only on the 396 engine and not the 427. I recently built an L-72 COPO Camaro engine with a COMP Cam LS6 Nostalgia+ cam, based on an article in Hot Rod that recommended that cam, and it had a rear groove and the cam bearings I used had only a single hole as I recall....did I screw up?

Thanks
Tim

[Duke W.]

Re: L-68/36 cam for 67

I'm not sure if you screwed up or not. The story is a bit complicated.

The grooved cam was the only BB SHP replacement cam for many years, so it's apparently okay to use the grooved cam in a '67-up block (with the correct single hole bearing), however, when using a grooved cam in a '67-up block it was initially recommended to solder up the bearing and redrill it to a smaller size (Chevrolet Power Manual), but IIRC this advice was later rescinded.


The '65-'66 blocks must have the grooved cam and "three hole" bearing, which is the transfer passage for oil to the lifter galleries and valvetrain.

Without the groove and three hole bearing in a '65-'66 block there is almost no oil feed to the lifters/valvetrain. Beginning in '67 this annular passage was machined in the rear cam bearing bore, and the OE cams didn't have the groove, and only a single hole bearing was required to just oil the rear bearing. Oil transfer to the lifters/valvetrain was through the annular passage machined in the bearing bore.

There was an extensive discussion on this issue about a year ago, and it should be in the archives. Joe and Clem were in on it and photos of the cam bearings were posted. If I screwed up this synopsis somebody please correct me.

A lot of guys get screwed by machine shops when they install the single hole bearing in a '65-'66 block.

The OE LS6 cam is the same as used on L-71 beginning in 1967, and it does not have a groove. Most aftermarket clones appear to have the groove.

The L-78/72 camshaft assembly (cam and indexing pin) with the groove is 3863143 and the casting blank for the 3863144 finished camshaft (less pin) has a groove, which was finish machined, and for many years this was the only listed SHP replacement cam. The non grooved equivalent is 3904362/3904366 and these were OE on L-71 and LS-6. The 362 did eventually show up as service parts briefly because apparently some were "found", but years after these engine were built.

A note on drawing number 3904366 says it is okay to use the blank used to machine the 144. In this case the groove must be fully machined rather than just finished machined since the blank for the 144 finished cam has a roughed in groove.

The aftermarket never seems to have sorted this out, but I think most replacements have a groove.

Duke

[John H.]

Re: L-68/36 cam for 67

Tim -

You have mail.