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Old 09-29-2022, 12:07 AM   #1
Warrens69GMC
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383 and roller cam for 78 c10

So I just bought a Smedling performance 383, and I have 72cc Summit heads and 67cc Summit Vortec heads. Looking for cam recommendations for my 1978 c10. I have a LT1 from a 1995 Camaro (705), AND A 94666492 Chevrolet cam for a Mercruiser. I also have a L31 cam. Which would you put in?

383, th350, 28 inch tall tires going with 3.23 with lsd. Probably a 1700 stall converter. looking for Torque 2500-4000rpm
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Old 09-29-2022, 03:19 AM   #2
Ziegelsteinfaust
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Re: 383 and roller cam for 78 c10

The Merceuiser cam from the specs I found would be a stronger performer at some rpm.

The L31 cam is nothing special, but would be a good driver.

So I would go with the 705 cam. It would be a great driver, and should get you around 350hp with some 400tq.
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Old 09-29-2022, 09:13 AM   #3
Warrens69GMC
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Re: 383 and roller cam for 78 c10

That was the one I was thinking of going with as it will have a decent idle, and will give all around performance.
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Old 09-30-2022, 08:56 PM   #4
garyd1961
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Re: 383 and roller cam for 78 c10

If you want a smooth idle you can't beat the L31 cam and vortec heads. I have the L31-R crate motor in my C10 and it's the smoothest idling 350 I ever owned. It still has good power with a lot of low end torque. If you want hp go with the LT1 cam and vortecs.
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Old 10-04-2022, 05:49 PM   #5
Tom
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Re: 383 and roller cam for 78 c10

No idea what the specs are for that marine cam but the oem vortec cam is so puny I can't believe anyone would put one in something that didn't already come with it in there. Lt1 cam all the way. Its still very small.
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Old 10-04-2022, 10:01 PM   #6
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Re: 383 and roller cam for 78 c10

Quote:
Originally Posted by Tom View Post
No idea what the specs are for that marine cam but the oem vortec cam is so puny I can't believe anyone would put one in something that didn't already come with it in there. Lt1 cam all the way. Its still very small.
Cam Style: Hydraulic roller tappet
Basic Operating RPM Range: 2,000-5,500
Intake Duration at 050 inch Lift: 214
Exhaust Duration at 050 inch Lift: 220
Duration at 050 inch Lift: 214 int./220 exh.
Advertised Intake Duration: 270
Advertised Exhaust Duration: 276
Advertised Duration: 270 int./276 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.452 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.465 in.
Valve Lift with Factory Rocker Arm Ratio: 0.452 int./0.465 exh. lift
Lobe Separation (degrees): 112
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Old 10-05-2022, 10:41 AM   #7
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Re: 383 and roller cam for 78 c10

I would definitely go with the Vortec heads assuming this engine has the dished piston that returns 9.8:1 compression with 65cc chambered heads. Given the relatively low static compression ratio, you will want to keep your dynamic compression ratio up by using a cam with reduced overlap, in my opinion. I think, given this combination, I would go with the Mercruiser cam. Should be a torque monster!
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