BBC GM 3904362 Camshaft Questions

goinforbroke · #1 05-24-2009, 02:42 AM

I recently picked up this NOS, in GM packaging camshaft. part number 3904362. Is it the same as an LS6/ L78 cam? I currently have a small Isky solid in my .030 over 454 oval 9.5:1 comp engine with specs of 228* @ .050 Duration, .520 lift 108*lsa. Would this cam do me any better? If not, would any of you guys be interested in it? I have no idea what it's worth but, it really is like new, only out of the tube to look at, still wrapped in plastic w/ GM label on it.
I'll try to shrink down a pic to send later tonight or tomorrow.
Thanks a lot.
John

**Mr70** · #2 05-24-2009, 06:47 AM

I believe it is identical to the #143 cam.This same cam was used on certain 1967-71 solid lifter 396,427 & 454's.
Specs for it..
.520 intake lift
.520 exhaust lift
316 intake duration
302 exhaust duration
1.70 rocker ratio
Does it reflect a casting symbol of OMO?

JoeG · #3 05-24-2009, 05:12 PM

Ditto Rick..........same cam--------part number was just changed

**69SSZL1** · #4 05-24-2009, 06:40 PM

Try this: http://www.geocities.com/MotorCity/D...00/cmspec.html
the factory did make some changes on casting# 3904366, part# 39043362 camshaft over the #143 cam. Valve events and duration are a little bigger.

JLerum · #5 05-24-2009, 11:11 PM

[ QUOTE ]
Try this: http://www.geocities.com/MotorCity/D...00/cmspec.html
the factory did make some changes on casting# 3904366, part# 39043362 camshaft over the #143 cam. Valve events and duration are a little bigger.

[/ QUOTE ]

If the specs are different on the measurement, I would assume that it is the variance in production tolerances.

Jim

PS.....Colvin has a blue print in his "Chevrolet by Numbers 70-75" in the camshaft chapter on the 3904366 casting.

**markjohnson** · #6 05-25-2009, 12:59 AM

That's the exact cam that came out of my 1970 LS-6. The lift is actually the same as the #143 camshaft. The .520 specification includes the lash. Subtract the lash figure and its' back down to right around .500 lift. I'm sure there's better, more modern camshafts out there, but I used to run 11.80's with mine with a really nice idle quality and good valvetrain reliability. In fact, it really doesn't sound like much of a camshaft, doesn't really thump very hard at all and I was always tempted to change it out until I'd give it hell on the service road in front of my house. Then I'd remember why I left it alone!

goinforbroke · #7 05-25-2009, 02:01 AM

Thanks for the information. Still unsure if I should use it or not. I went very mild with my initial cam selection because I was running an automatic. Now with a 4 speed in the works, this one is slightly more aggressive (duration) with just a wider lsa. Mr 70, it does have a casting mark that looks like CMC but, it could be OMO.

**Mr70** · #8 05-25-2009, 06:22 AM

My L78 Chevelle is turning this shaft,and like Mark,I was considering replacing it soon afterwards.That was up until I took it out on the open road after the engine gelled,then it was obvious to me I needed to buckle up.
That's a good cam to have..

Joe Sikora · #9 11-15-2020, 03:58 AM

(Coming in late to this discussion but wanted to chime in with some things I found out looking into the 3904362 I got from the dealer when I built the motor for my 67 Corvette back in the late 90's)

I was told at the time this was the new number for the 3863143 cam beginning in 1988 (66-69 427 Sp Hi Perf, and is a mechanical cam based on lifter application). My engine build notes say the 362 cam was identified 921559 on the end. An important difference is the NOS 3863143's I've seen all had grooved rear cam bearings. The 362 cams were all the later style without the groove.

3863143 Cam:
https://www.yenko.net/forum/showthread.php?p=1251981
https://www.yenko.net/forum/showthread.php?t=149138
https://store.tracyvette.com/item/1676/

3904362
https://www.ebay.com/itm/NOS-GM-Soli...-/333739856437