BBC GM 3904362 Camshaft Questions

[69SSZL1]

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]

[ 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]

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]

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]

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..