Camshaft manufacturing

[Warren F.]

I have a GM new old stock cam, that I would like to get exactly duplicated so I don't have to use the original. It was extremely difficult to find and cost a lot.
Can someone recomend a reputable firm to do this? I certainly don't want this camshaft lost.

[John H.]

Re: Camshaft manufacturing

Warren -

Which cam is it? Crane has "blueprint" versions of just about every vintage GM cam, most of which carry GM part numbers (they make all the cams for GM Performance Parts too).

[Warren F.]

Re: Camshaft manufacturing

John,

I have a 3904362 part # with 3904366 stamped on end. This should be the truly original cam for the '70, '71 LS-6.

[Terry D.]

Re: Camshaft manufacturing

Warren

Just curious as to why you want to save the cam? What good is it if you don't use it? Nobody sees it, not trying to be a smart a__. Just curious.
Terry

[Joe L.]

Re: Camshaft manufacturing

Warren----

I agree with John; there's absolutely no need to send in a camshaft for duplication (at least, one that has very well-known specifications to the camshaft grinder). This, particular, camshaft is reproduced (sort of). You can get a reproduction of the GM #3863143 very easily from several different manufacturers, including Crane. Unfortunately, the GM kit which included the Crane-manufactured camshaft and lifters has been discontinued. The main reason that's unfortunate is that the kit was a VERY good value. You can still get the camshaft from Crane or most of the other manufacturers, too.

The GM #3863143 that's reproduced is EXACTLY the same as the GM #3904362 EXCEPT that it has an oiling groove on the rear journal (for 65-66 engines).

In any event, if you want a camshaft without the rear journal groove (i.e. the 3904362) all you need to do is contact Crane or Competition Cams and tell them what you want. Both firms have "custom camshaft manufacturing divisions" and can grind a cam to specification. So, you just tell them that you want a GM #3904362 specification camshaft. They have the specs for that. If they don't (VERY unlikely), then you just tell them that's it's the same as the 3863143 with no rear journal groove.

Be prepared for one thing, though: if you obtain the cam through their "custom manufacturing division" you are going to pay WAY more for it than if you just get one of their 3863143 off-the-shelf reporductions.

How close will a Crane or Comp Cams reproduction be to the original camshaft specs? It will be as close or closer to the original specifications as the original GM cams manufactured to those specifications. With the type of equipment that Crane and Com Cams have now, they can undoubtedly hold better tolerances than GM did back in the days of mass production.

[Duke W.]

Re: Camshaft manufacturing

Federal Mogul Speed Pro offers an off the shelf replacement, CS165R, but I think this cam has the rear journal groove as used in the earlier version for L-78/72, so it's really the 3863143/4 cam. Other than groove/no groove these two cams are identical - same lobes and indexing.

It's my understanding the a grooved rear journal cam is okay to use in post-'66 engines that did not have an OE grooved rear journal cam, but you can't use the non-grooved cam in earlier blocks.

That's why Chevrolet never cataloged the 362 cam in service parts. The 143 was listed in the parts book as the service replacement for all '65-'71 396/427/454 SHP.

Duke

[Warren F.]

Re: Camshaft manufacturing

Terry,

I have 2 original LS6 Corvettes and want to start driving them a lot more, neither has ever had any engine work done to them, I really like having a true 454 cid engine, with no aftermarket pieces. I want a spare for each car, if I could find another one of these cams, I would buy it.

[Lyndon S.]

[Lyndon S.]

[Warren F.]

Re: Camshaft manufacturing

Joe,

Thank you, as always your information is extremely helpful.

[Warren F.]

Re: Camshaft manufacturing

Duke,

I really appreciate the information, I was concerned that the lobe separation degree or the valve overlap degree was not exactly the same. All I can find for specs is 519.7 lift and intake duration .316 and exhaust duration .302. I thought the previous two measurements were 80 and 114 or something like that. If there are no differences, then I won't worry about it anymore.

[Lyndon S.]

Re: Camshaft manufacturing

Warren

You say that you want a true 454? What if you have some wear on the block, and it would clean up with a 30 thousandth over bore, would you just have the whole blocked sleeved so that it would remain a true 454cid? I know a lot of questions just want to know you thought process on what your saying ?

[Warren F.]

Re: Camshaft manufacturing

Kelly,

I have 2 original LS6 cars currently. One has a flat lobe on #3 cylinder, due to the previous owner using normal oils without the added protection of the ZDDP and sulphur additives. This car has 60,013 miles on it. The other car has just 36,279 miles and I switched to Shell Rotella 15W-40 after reading about the problems occuring (old formula, not new one)

I bought this cam to be sure I had an original OEM unit to install in the orange car (that needs one), however when the white car will need one, I wanted to have an EXACT duplicate, since finding these camshafts has been extremely difficult to locate and purchase. Also I have heard conflicting information as to whether the 3863143 and 3904362 cams, were indeed exactly the same specifications.

[Warren F.]

Re: Camshaft manufacturing

Kelly,

I've sure thought about that; and I have contemplated on what I would do in that circumstance. I've heard opinions that sleeving is not the best avenue to take, unless a valuable block, and no other recourse to save it.

I have OEM NOS pistons at .001, .010, & .030 for just such a case. I wanted to truly say that the engine is STOCK, but if I use these then its not. I like having the factory power and tuning it to the inth degree with factory stock set-ups. It's fairly easy to build a non stock performance engine, it's something else to have a factory stock engine run and perform extremely strong. Quite satisfying when it happens.

[Warren F.]

Re: Camshaft manufacturing

Kelly,

I have heard people mention that you can get a camshaft reground, I just don't know how they would know exactly the specifications, with an original there, to compare it to. Are these cams hardened like originals, and will they work with stock GM lifters 5232695 part#? Is this a worthwile endeavor to look into?