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Old 12-11-2011, 08:20 PM
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BigEd36 BigEd36 is offline
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Howards gives the description for that cam as "Great daily usage, smooth idle, great fuel economy." The rpm range given is 800-4200 rpm, so it will pull right from idle. The cam and compression ratio chart that techinspecter1 linked to shows that 9.25:1 needs 208 degrees at .050", 9.5:1 needs 212 degrees. Your 9.4:1 falls between them so 208-212 degrees. The Howards is 207 degrees at .050" so it's pretty close. Hopefully techinspecter1 will chime back in on this. GM usually uses pretty long and gentle ramps so I suspect the Howards cam may be shorter on total duration (which will give more torque) even tho it's bigger at .050".

Another cam that would work well is GM #14097395. This is the cam used in the 383HT (383 High Torque) and 350 Ram Jet crate engines. It's $177.12 at Pace Performance Here's the description from the Pace Parts website:

This hydraulic roller design is used on the 383 truck and Ramjet 350.

The duration at lash point in degrees (intake/exhaust) is 288/308; duration at .050" tappet lift (intake/exhaust) is 196/206 and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 431/451. Valve lash is zero/zero and lobe centerline is 109 degrees.

This camshaft is a great upgrade for 1996-2000 Chevy/GMC trucks equipped with the L31 Vortec 350 Engine. This cam is great for additional bottom end torque. If installed in one of these trucks, a custom computer re-program is needed.
The 383HT I notice this GM cam uses 288* advertised for a 196* @ .050", that gives 92* for the ramps. If they used the same rate of ramps for the stock cam it would make the total duration approx. 283* for 191* @ .050". This reinforces my suspicion that the stock cam probably has more total duration than the Howards cam, even tho the Howards cam has more at .050". "More area under the curve" to put it in the language that the cam companies use to advertise their cams.

I believe either of these cams would be a worthwhile upgrade to your Vortec 350.
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