LS5 camshaft

[Justin S.]

Hi all, In the process of tearing down my '70 LS5 I was pleasantly surprised to find original bearings. I was also surprised to find no part number on the camshaft. There are, however numbers stamped in between lobes. In between the rear 3rd and 4th is stamped GM 30 30. Further towards the center of the cam are the numbers 4364. I appreciate any explanation

Thanks,
Justin Sibbring

[Duke W.]

Re: LS5 camshaft

You found the abbreviated part number, which is used to identify the custom cast blank. The full part number/drawing number is 3904364. The GMPD number that consists of an assembly of camshaft and indexing pin is 3904359.

This camshaft/pin assembly is the same as 3883986 used on '66 390 HP big blocks except ...359 lacks the rear journal groove that is necessary for the '65-'66 big block oiling system. The ...986 can also be used on '67-up big blocks that don't require the rear journal groove, and in fact, most P & A catalogs show the ...986 as the replacement for all Corvette hydraulic lifter big blocks through '72.

The lobe design and phasing are close to the small block L-79 cam - just slightly milder, which makes for a very torquey engine that still has respectable top end power.

An exact replacement is Sealed Power CS1093M or Clevite 229-1953, and I don't think either have the rear journal groove, so it must be cut for installation in a '65-'66 block and used with the early three-hole bearilng.

I hope you measured deck clearance of all eight cylinders before you removed the pistons so you can get a handle on managing the compression ratio for the rebuilt engine.

Duke

[Justin S.]

Re: LS5 camshaft

Thank you so much Duke for the information!!

Justin

[Joe R.]

Re: LS5 camshaft

Justin,

I think this is the cam that Duke described to you in the above thread.

JRDSCN4137.jpgDSCN4138.jpg

[Duke W.]

Re: LS5 camshaft

How did you acquire that cam, Joe?

As you probably know, it was never cataloged, but it was an active part number for a while, and Joe Lucia managed to snag a few examples.

It was discussed in the following recent thread.

https://www.forums.ncrs.org/showthre...04359+camshaft

Duke

[Donald A.]

Re: LS5 camshaft

Great information!! Justin what is you ViN? Convertible or coupe?

[Joe R.]

Re: LS5 camshaft

Duke,

Snagged them just like Joe L. Ordered from Chevy. There was a discussion besides the one you posted and I gave the part number. Think I got it thru one of the speed catalogs or something like that.

JR

How did you acquire that cam, Joe?

As you probably know, it was never cataloged, but it was an active part number for a while, and Joe Lucia managed to snag a few examples.

It was discussed in the following recent thread.

https://www.forums.ncrs.org/showthre...04359+camshaft

Duke