L82 Cam Specs

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Jul 26, 2016 | 07:23 AM

biackbenz

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Drifting

Joined: Apr 2004

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From: Mequon WI

L82 Cam Specs

I've searched but have not found it? What are the original cam specs for the '78 L82?

In today's technowlogy, what is a current cam that meets this original cams performance?

Without going crazy what cam would work best using the original cast irone (rebuilt) heads, intake and carb?

Would replacing the exhaust manifold with a long tube header change your recommendation?

Not sure what gears I have in the rear end but car tachs about 3300 RPM@ 70 MPH.

Thanks

Jul 26, 2016 | 07:34 AM

jb78L-82

Le Mans Master

Joined: Oct 2007

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From: Tennessee/Rhode Island

L-82 cam.......450/.460 Lift, Duration 222, LSA 114

Before I went Roller cam I was looking at the Lunati Voodoo Flat tappet cam 262/268 for some increase in performance:

Lift .468/.489
Duration-219/227
LSA-112

Operating range of cam-1,300-5,500 RPM-good bottom end, strong mid range, decent power to 5,500...certainly better than the L-82 cam

Last edited by jb78L-82; Jul 26, 2016 at 07:35 AM.

Jul 26, 2016 | 07:57 AM

GOSFAST

Burning Brakes

Joined: Feb 2005

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Quote:

Originally Posted by jb78L-82

L-82 cam.......450/.460 Lift, Duration 222, LSA 114

Not a big deal but the duration is 224* and this is one nice all-around street cam for any basic SBC! The 222* duration was on the 327"/350 HP platform.

Thanks, Gary in N.Y.

P.S. We still manage to sell a fair amount of these cams during the course of any business year! We've had decent HP numbers on the pump-gas 350" on some dyno tests also, using this cam.

Last edited by GOSFAST; Jul 26, 2016 at 07:58 AM.

Jul 26, 2016 | 09:31 AM

jb78L-82

Le Mans Master

Joined: Oct 2007

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From: Tennessee/Rhode Island

Quote:

Originally Posted by GOSFAST

Just for clarity, Gary, every source I have for The L-82 cam has a duration of 222, not 224. Where did you source the 224 number?

Here are 2 sources I just looked up:

http://paceperformance.com/i-6255716...hydraulic.html

http://www.jegs.com/i/Chevrolet-Perf...96962/10002/-1

I have always thought the duration was 222?

Last edited by jb78L-82; Jul 26, 2016 at 09:34 AM.

Jul 26, 2016 | 11:36 AM

Barry's70LT1

Melting Slicks

Joined: Oct 2001

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From: Halifax, Nova Scotia, Canada

Here are the specs for many GM cams.

Jul 26, 2016 | 12:11 PM

jb78L-82

Le Mans Master

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From: Tennessee/Rhode Island

Interesting but does not explain the GM L-82 cam below with the same part number. Does anyone know for sure what the L-82 cam duration is @ .050 for sure? I have been quoting the 222 number forever so just want to know exactly what the duration is if someone knows for certain?

Chevrolet Performance 3896962 - Chevrolet Performance Hydraulic Flat Tappet Camshafts

Chevrolet Performance 3896962 - Chevrolet Performance Hydraulic Flat Tappet Camshafts
Representative Image
Product images may differ from actual product appearance.

JEGS Part Number: 809-3896962

Hydraulic Flat Tappet Camshaft •1968-81 Small Block Chevy L-46 and L-82 Corvette
•222 / 222 Duration @ .050''
•.450'' / .460'' lift
•114 Lobe Separation Angle

Clearly some sources say 224 and others say 222.......................

Also for you cam experts, the reason I was looking at the Lunati Voodoo 262/268 as a replacement for the L-82 cam at one time, my understanding the extra lift coupled with the split duration of 219/225 would produce noticeably more power than the stock L-82 cam even with stock heads? Yes?

Last edited by jb78L-82; Jul 26, 2016 at 12:17 PM.

Jul 26, 2016 | 01:16 PM

gkull

Team Owner

Joined: Apr 1999

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From: Reno Nevada

2024 C3 of the Year Finalist- Modified

These are the numbers I have seen since buying my 79 L-82 nearly 37 years ago.

Chevrolet Performance 3896962
•222 / 222 Duration @ .050''
•.450'' / .460'' lift
•114 Lobe Separation Angle

Barry's70LT1 posting of GM cams might be corporate deception so other builders are thrown off slightly. I have worked on some of the original big block racing corvettes now raced in Historic motorsports association.

Just for the fun of it over beer after work we pulled a new in the box GM off road mechanical cam out and rigged it up with dial indicators and it measured different and lower numbers than the cam card. I'd say deceptive. But this was a very radical cam. If you ever get a chance be in the pit area when they are warming a group of them getting ready for their heat races like at the up coming Monterrey Historics! We usually took a couple of Can-Am cars and I was a pit crew person.

http://vid124.photobucket.com/albums...t044_WMVV9.mp4

Last edited by gkull; Jul 26, 2016 at 01:17 PM.

Jul 26, 2016 | 04:10 PM

v2racing

Melting Slicks

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From: Spring Park MN

Quote:

Originally Posted by jb78L-82

The extra lift isn't significant enough to make much difference especially since stock heads flow stalls out at around .450 lift. The duration change isn't enough to make much difference either.

The parts of the Voodoo cam that would make a difference is the more aggressive lobes which have less duration below the .050 spec and more above it with a broader nose. This will give more area under the curve for better cylinder fill. The tighter lobe center would give slightly more overlap. The tighter LSA along with the shorter duration would give an earlier closing intake valve that would help bottom end power. The aggressive lobe with less duration at .006 would make for better bottom end also. The combination would make for a little better usable power, nothing big though.

Mike