Help with camshaft stamped 3883944

[Daniel W.]

Hello,
I am researching a camshaft I have in a cardboard tube without the GM part number on the tube. The cam is stamped 3883944 on the end of the shaft. Does anyone know the application for this cam?

Thank you,
Daniel Wilson

[Peter S.]

Re: Help with camshaft stamped 3883944

Hi Daniel,

That sounds like the 1969 427/400 HP camshaft.

Peter

[Edward B.]

Re: Help with camshaft stamped 3883944

The 3883944 casting was used on the 1966 396/350, the 1966 427/390, the 1969 396/350, the 1969 427/390 and the 1969 427/400. Ed

[Joe L.]

Re: Help with camshaft stamped 3883944

The 3883944 casting was used on the 1966 396/350, the 1966 427/390, the 1969 396/350, the 1969 427/390 and the 1969 427/400. Ed

Ed------


That's what a lot of references say but it's not completely accurate. The 1966 snd, possibly, very early 1967 high performance big block applications (e.g L-34, L-36, L-68) did use this camshaft casting. However, it was not used for late 1967 and later high performance applications. Those applications used the GM #3904364. What's the difference? The 3883944 casting has a groove in the rear journal for 65-66 style oiling. The 3904364 has no such groove.

[Duke W.]

Re: Help with camshaft stamped 3883944

GM manufactured camshafts, at least during the period they were used in production, were ground from specific castings that had lobes close to finished dimensions in order to minimize machining time. There is no "casting number", but the finished camshaft part number was cast into the blank and is referred to in parts manuals as the "ID number".

Camshafts furnished to GMPD were actually "assemblies" that consisted of the camshaft and indexing pin. This is why the part number on the tube will be different that the number on the casting. Some are sequential, but some may vary by up to about 40.

The ...944 blank was cast with the rear journal groove and also had some finish machining to form a chamfer at the surface. The ... 364 blank was cast without the groove, however, a note on drawing number (the drawing number is the part number) 3903964 says it can be finished to a ...944 by machining the groove the the specified dimensions.

You say that 3883944 is stamped on the rear surface of the cam. What, if any, data is molded into the casting?

Also, does the rear journal groove appear to be fully machined or just machined near the surface with the interior of the groove appearing to be as cast?

Duke

[Edward B.]

Re: Help with camshaft stamped 3883944

That's what a lot of references say but it's not completely accurate. The 1966 snd, possibly, very early 1967 high performance big block applications (e.g L-34, L-36, L-68) did use this camshaft casting. However, it was not used for late 1967 and later high performance applications. Those applications used the GM #3904364. What's the difference? The 3883944 casting has a groove in the rear journal for 65-66 style oiling. The 3904364 has no such groove.

If that's correct (and I would agree that it probably is for the reason you stated), the misinformation appears to have started with the P&A's! My September, 1968 P&A 34 shows the P/N 3883896 (casting number 3883944) being used on the 65 Chevelle 396 and all 66-69 with 396/350 engines. My October, 1972 P&A 30B also shows this same cam being used on 66-69 427 and 70-72 454 engines (except special high performance or heavy duty). If you look at GMPartswiki, ALL of the P&A's show that cam being used from 65-72 in the 427 or 424 standard performance engines, so someone at GM publications must have screwed it up in late 1966 or early 1967 and it never got fixed. Heck, the P/N 3904359 (casting 3904364) isn't even shown in ANY of the P&A's! Another example of a mistake in the P&A's being carried over for multiple years. Ed

[Duke W.]

Re: Help with camshaft stamped 3883944

The early grooved big block camshafts could be used in later engines, so apparently GM didn't catalog the non-grooved versions.

Advice in the Chevrolet Power Manuals from the seventies advised that using a grooved camshaft in a '67-up block required modifying the rear cam bearing hole, but this advice was apparently later rescinded.

Joe reported a few years ago that apparently GM "found" some non-grooved big block cams about 10 years ago and they briefly appeared in the P & A catalogs until inventory was exhausted.

Current Federal Mogul OE replacement cams cross reference from the early grooved part numbers, however they don't have the groove, which must be machined when used in '65-'66 blocks including the companion three-hole bearing.

Duke

[Joe L.]

Re: Help with camshaft stamped 3883944

If that's correct (and I would agree that it probably is for the reason you stated), the misinformation appears to have started with the P&A's! My September, 1968 P&A 34 shows the P/N 3883896 (casting number 3883944) being used on the 65 Chevelle 396 and all 66-69 with 396/350 engines. My October, 1972 P&A 30B also shows this same cam being used on 66-69 427 and 70-72 454 engines (except special high performance or heavy duty). If you look at GMPartswiki, ALL of the P&A's show that cam being used from 65-72 in the 427 or 424 standard performance engines, so someone at GM publications must have screwed it up in late 1966 or early 1967 and it never got fixed. Heck, the P/N 3904359 (casting 3904364) isn't even shown in ANY of the P&A's! Another example of a mistake in the P&A's being carried over for multiple years. Ed

Ed------


That's because the 3883896 was the only cam ever cataloged in SERVICE for the 66-72 high performance hydraulic lifter applications. However, it's not the cam used in PRODUCTION for the L67-72 applications.

As Duke mentions, several years ago I discovered that the 3904359 camshaft actually was available in SERVICE. They were never actually cataloged, though, since the catalogs that would have included them went inactive (i.e. no longer updated or printed) apparently before GM discovered they had the camshafts. I purchased about 5 of them [none for sale] before the existing stock was exhausted. I assume it was a very small inventory.

[Duke W.]

Re: Help with camshaft stamped 3883944

So, Joe, if they were never cataloged, how did you find them? In the era that you found them was GM using paper, microfiche, or online technology?

Duke

[Joe L.]

Re: Help with camshaft stamped 3883944

So, Joe, if they were never cataloged, how did you find them? In the era that you found them was GM using paper, microfiche, or online technology?

Duke

Duke------

It was sort of an interesting happenstance. The SHP mechanical lifter cam, GM #3863143, was discontinued in February, 1988 and replaced by the GM #3904362. This change occurred long after the last catalogs referencing this camshaft went inactive. Still, the change was reflected in both the microfiche history and electronic parts systems so while there was no change possible in the catalogs, the change was established in the system. So, if one went to a GM dealership parts department and asked for a GM #3863143 after February, 1988, one would have been told it was no longer available but a replacement, the GM #3904362, could be ordered. In February, 2000 the GM #3904362 was discontinued without supercession and "that-was-that" as far as the SHP cam was concerned.

The GM #3883986, high performance hydraulic lifter cam, did not follow this same pattern. It was discontinued without supercession in August, 1999. So, that strongly implies at the very least that no supercessive part was available. One day I thought to myself I wonder why the 3883986 did not follow the pattern of the 3963143? So, I checked the electronic system. Lo-and-behold, I found that the non-grooved-rear journal equivalent of the 3883986 (and the camshaft actually used in PRODUCTION for L67-72 HP hydraulic lifter big blocks), GM #3904359, was available. I couldn't believe my eyes. I figured it was some kind of mistake. So, I ordered one. I got it. So I successively (i.e. one at a time) ordered 4 more. When I ordered the 6th one, it came back discontinued. I did this all back in the early 2000's.

[Daniel W.]

Re: Help with camshaft stamped 3883944

Duke,
I cannot locate any casting numbers anywhere on the cam. With the exception of the stamped 944 in the rear, there is some blue paint near the #2 journal surface that was not machined away when that journal was cut.

The rear journal groove is cast into the piece, not machined. The bottom of the groove is clearly "cast" between the machined surfaces of the rear journal. The groove is 0.110" deep and 0.180" wide.

Dan

[Joe L.]

Re: Help with camshaft stamped 3883944

Duke,
I cannot locate any casting numbers anywhere on the cam. With the exception of the stamped 944 in the rear, there is some blue paint near the #2 journal surface that was not machined away when that journal was cut.

The rear journal groove is cast into the piece, not machined. The bottom of the groove is clearly "cast" between the machined surfaces of the rear journal. The groove is 0.110" deep and 0.180" wide.

Dan

Dan------

I'm not sure I understand here. In your original post you said the number 3883944 was stamped on the rear of the cam but in this post you seem to be saying it's just 944.

In any event, if the number is 3883944 I'm sure that's a GM camshaft (it would be illegal for anyone other than GM or its authorized suppliers to stamp this number on a camshaft) and, likely, a SERVICE camshaft. As I mentioned before, after their use in PRODUCTION ended, I believe GM pretty much went to "generic" cores. However, the camshafts were still manufactured at the engine plants or Bay City, MI engine components plant. It's very possible that, at least for a time, the "generic" cores were available with or without the rear journal groove.

[Duke W.]

Re: Help with camshaft stamped 3883944

...just want to confirm, Dan, but are you saying that there are NO letters, numbers, or symbols molded into the blank. Even generic cores have data molded in. Most currently available OE replacement camshafts have "CWC" molded in and other data/symbols. "CWC" is the CWC division of Textron, which makes generic cores that the aftermarket uses to grind finished camshafts - both OE and non-OE designs.

Even if what you have is a generic GM-cast big block core, I would expect it to have some kind of ID information molded into the casting, however, it's possible that the blotch of blue paint is the only ID.

I agree that with Joe that what you have is probably a GMPD service camshaft that was manufactured after that particular camshaft was no longer used in production engines.

Thanks for the information.

Duke