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Topic: Factory Cam Specs

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Factory Cam Specs

Posted: 2/4/07 4:44pm Message 1 of 7
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Red Lion, PA - USA
Joined: 10/27/2006
Posts: 1182
Vette(s): 1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic
I am searching to find what the original cam specs would have been on my 1974 Corvette 4 BBl engine with 195 HP with auto trans. Can anyone direct me to a page that would have this information. I am considering doing an upgrade but I would like to know original specs before buying. Also if you would have recommendations I would like to hear them. I plan on keeping the stock look so I will probably be painting an aftermarket intake chevrolet orange and I will be keeping the stock ram horn  manifolds as well. Not sure if I will be changing the ignition yet or not. I really would like to keep the stock look.
Thanks
Rodney




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Factory Cam Specs

Posted: 2/4/07 8:44pm Message 2 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Possibly the Chevy engineering papers would have that specific info, but where the heck would you find that?
I know I can get you the original part number for the cam, but I don't know about the cam specs. Have you contacted any of the major cam grinders? They would be your best bet for the stock spec info, as they would have replacement cams available.


Joel Adams
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Factory Cam Specs

Posted: 2/4/07 9:46pm Message 3 of 7
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Red Lion, PA - USA
Joined: 10/27/2006
Posts: 1182
Vette(s): 1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic
I will call the local GM parts tomorrow and see if they can get that information. I just want to know how much of a difference other cams are. I checked the service manual but no specs listed.
Joel, is your engine stock or have you done some modifications to it? If so do you have pics of your engine? I want to keep a stock appearance but want to make some changes as I go. 
Thanks
Rodney




Factory Cam Specs

Posted: 2/5/07 5:58am Message 4 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
The '74 is 100%, St. Louis installed, factory, except for plug wires/plugs, points/condenser, upper rad. hose, oil & air filters. Even have the orig. belts.
I do have a few(thousand) pics...I'll put some up later.


Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Factory Cam Specs

Posted: 2/5/07 1:02pm Message 5 of 7
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Rodney, here's what I had in my files. The specs are for a stock L-48 cam, so I don't know if they're identical to what you have in your '74 or not. Since you said 195 HP, I'm assuming it is the same engine. Nor can I vouch that these are in fact the correct specs--I copied them from some source that I no longer recollect.

That said, what I have is:

Stock L48 cam specs are: Intake: 195 Duration @ .050" , Lift .390" Exhaust: 202 Duration @ .050" , Lift .410" Lobe Separation 112

Hope this is some use to you--


Factory Cam Specs

Posted: 2/5/07 10:22pm Message 6 of 7
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Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas
Wow...it's a wonder these things will even start & run!! If those are the correct specs, and I'm betting they are, Chevy was taking a beating on emissions! That's the only reason they would have used such lousy specs for a Corvette. 195deg duration?!?!? jeeeeeeezz! I bet my ol' chain saw has more than that!
I've never seen the factory specs for the mid-70s cars, so this is really an eye opener. With a 9/9.5 comp. ratio, I would rather see something in the 270-280 range on intake duration, and around 275-290 on the exhaust, with a .480 lift. Then that little ol' L48 would wake up!
Yeah, I might give up a bit of fuel mileage, and it might be a little tough to start in da mornings when it's cold, but...


says the guy who never drives his car anyway...


Joel Adams
C3VR Lifetime Member #56    

My Link


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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Factory Cam Specs

Posted: 2/6/07 4:46pm Message 7 of 7
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Red Lion, PA - USA
Joined: 10/27/2006
Posts: 1182
Vette(s): 1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic
I used to work at a Pontiac dealership many years ago and I gave my old friend at the parts department a call today to see if he could give me the specs for my factory cam. His findings were as follows, Exhaust lift .403 - exhaust duration @.050 - 202   /   Intake lift .384, intake duration @.050 - 194, lobe seperation 104 degrease.
Now compare that to what Summit proposed in one of their extreme energy cam kits: Intake @ .050 - 218 Exhaust @ .050 224, advertised duration 262/270, intake lift with factory rocker arm ratio .462  exhaust lift with factory rocker arm ratio 469. Lobe seperation 110

What I am looking for is adding some HP without hurting the drivability. I do not want a real lopey sounding cam, or something that loads up sitting and idling. I plan on driving this with my wife on short weekend trips.

Let me know your thoughts. Maybe I should just let it stock?





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