Anyone know the specs of a 77 L-48 cam? - CorvetteForum - Chevrolet Corvette Forum Discussion


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Anyone know the specs of a 77 L-48 cam?

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Old 03-15-2012, 11:50 PM   #1
daanbc
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Default Anyone know the specs of a 77 L-48 cam?

I want to compare it to the one I will be installing soon. Thanks..
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Old 03-16-2012, 12:17 AM   #2
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Just think pitiful lol. .390/.410 lift, 195 at .050 duration.

Last edited by Little Mouse; 03-16-2012 at 12:20 AM.
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Old 03-16-2012, 01:04 AM   #3
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Thank you.
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Old 03-16-2012, 01:42 AM   #4
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Quote:
Originally Posted by daanbc View Post
I want to compare it to the one I will be installing soon. Thanks..
More information at the link below on page 80 of 111:

http://www.gmheritagecenter.com/gm-h...tion-kits.html

Click on the link above. Scroll down the page to "Corvette" and select "Show". When the new page opens, select the year you want - in your case "1977". Accept the Usage Agreement and a pdf will down load.

This pdf contains the Manufacturer Vehicle Data for that year and model. It also contains Chevrolet Dealer Sales information for that particular year.

Page 80 has the cam information. Lots of other useful information in the pdf.
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Old 03-16-2012, 10:48 AM   #5
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THANKS, I had that on my "favorits" and somehow lost it then forgot about it. Thanks again!
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Old 03-16-2012, 12:36 PM   #6
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I have a twin of your car, 77 L48, orange. Are you just doing the cam, or is this part of a larger project? Though my car runs great, it def needs more oomph.
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Old 03-16-2012, 02:00 PM   #7
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i hopes it to make sure its not like the one you are putting in.....maybe you know all this allready but if not read up on breaking in a cam. bob
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Old 03-16-2012, 03:54 PM   #8
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I have a twin of your car, 77 L48, orange. Are you just doing the cam, or is this part of a larger project? Though my car runs great, it def needs more oomph.
Check my recent posts, I have listed the things that I did so far.
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Old 03-16-2012, 07:49 PM   #9
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i believe the factory replaced the L-48 cam with a broom stick.
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Old 03-16-2012, 11:15 PM   #10
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Default Now thats a more difficult question.

I had to look in 2 reference books for the full specs. But it was kind'a interesting in that the L48 used the 3896929 cam (known as the 929) from '69 to '81 and it was the first year of a dual pattern cam for chevy. Well chevy listed it with a 327" motor as 300hp. But when D. Vizard built a 350" around the 929 cam it was just busting 300hp using 10.1 compression and some blueprinting.

Anyways using Corvette by the Numbers i found for the '77 L48 the 3896929 cam with 310* full duration on the intake and 320* full duration on the exhaust. Identified by a Diamond casting symbol (in front of the first lobe i think). And this differs from the reference mapman has with 280* on the intake and 288* on exh. But the heritage archive does have the vlv timing of 28-72-78-30 which supports their full duration numbers.

Now for the remaining specs i used Ed Staffel's sbc interchange manual. This lists cam part #3896929 as a hyd flat tappet with 0.050" duration of 195* intake and 202* for exh making 300hp in a 327" sbc. Lobe separation angle was 112 degrees.

The "929" earned its keep in performance cars, work trucks and grocery getters. Maybe seems outdated but the 260hp H echo in Mehico sbc crate engine for $1500 has a very similar cam. I honestly think if more owners spent more time on tuning and increasing compression that stock 929 could be made fun to drive in a vette. Not gobs of power but still fun to drive.

Ok, i'll shut up now,
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Old 03-16-2012, 11:31 PM   #11
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Quote:
Originally Posted by cardo0 View Post
i had to look in 2 reference books for the full specs. But it was kind'a interesting in that the l48 used the 3896929 cam (known as the 929) from '69 to '81 and it was the first year of a dual pattern cam for chevy. Well chevy listed it with a 327" motor as 300hp. But when d. Vizard built a 350" around the 929 cam it was just busting 300hp using 10.1 compression and some blueprinting.

Anyways using corvette by the numbers i found for the '77 l48 the 3896929 cam with 310* full duration on the intake and 320* full duration on the exhaust. Identified by a diamond casting symbol (in front of the first lobe i think). And this differs from the reference mapman has with 280* on the intake and 288* on exh. But the heritage archive does have the vlv timing of 28-72-78-30 which supports their full duration numbers.

Now for the remaining specs i used ed staffel's sbc interchange manual. This lists cam part #3896929 as a hyd flat tappet with 0.050" duration of 195* intake and 202* for exh making 300hp in a 327" sbc. Lobe separation angle was 112 degrees.

The "929" earned its keep in performance cars, work trucks and grocery getters. Maybe seems outdated but the 260hp h echo in mehico sbc crate engine for $1500 has a very similar cam. I honestly think if more owners spent more time on tuning and increasing compression that stock 929 could be made fun to drive in a vette. Not gobs of power but still fun to drive.

Ok, i'll shut up now,
Cardo0
thanks a whole bunch!!!

Last edited by daanbc; 03-17-2012 at 12:26 AM.
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Old 03-17-2012, 10:22 AM   #12
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In '77 was it installed straight up or retarded for emissions? That would have a big effect on power...
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