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modifying an L-82

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Old Jun 26, 2007 | 03:50 PM
  #21  
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Nope, your L-82 or GM 3896962 is ground on a 114 LSA same as the GM "151" cam. Both cams are very similar with the exception that the "151" is ground 4 degrees advanced on a 110 Intake Center Line (ICL) for the shorter stroke of the 327 and the L-82 cam has a bit more lift. Even being on a 110ICL, I install the "151" 4 degrees advanced for stump pulling torque.

BTW, you will not gain much in compression by using a .019" or even a .015" thick head gasket since the stock GM gasket on your engine is already a shim gasket at .021".
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Old Jun 26, 2007 | 04:01 PM
  #22  
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Nope, your L-82 or GM 3896962 is ground on a 114 LSA same as the GM "151" cam.
Good to know. I really should check my book before I make assumptions, but its at home. But what if I did use a 112 LSA? How about the power loss at low RPM? And what about vacuum? Obviously people use alot tighter LSAs so vacuum, I'm assuming, shouldn't be a problem right?

BTW, you will not gain much in compression by using a .019" or even a .015" thick head gasket since the stock GM gasket on your engine is already a shim gasket at .021".
Should I really be concerned about compression? Now I know the L-82 sports a 9:1, but if I could bump it up closer to 9.5:1... Is that possible with the stock components? I dont' ahve to worry about iron heads yet at 9.5:1 do I?
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Old Jun 26, 2007 | 04:13 PM
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Originally Posted by foxymophandlpapa
Last I checked my book listed the L-82 at 112 LSA. Would 110 LSA really "kill" the low RPM torque? Even with the extra modifications?
If I understand the question, you can not easily compare 2 completely different profiles that way. Take one particular grind and change the lobe centers and you might have a more valid comparison that will fit with a general statement. Lobe centers differrent with all else being equal and the comparison works.

110 degree lobe centers will not exactly "kill" the bottom end but it is more of a compromise. The L-82 cam doesn't have much bottom end to begin with so you can see that it isn't easy to compare it to aftermarket grinds.

GM cams are ground very differently as compared to aftermarket grinds. You can not easily compare the typical aftermarket specs to GM specs and get anything meaningful.

Bottom line - you have to decide if you want "stock" sounds, appearance and manners with high performance OR do you want to move away from "stock" and build more of a hot rod that will not be mistaken for stock when idling, give away some manners but give you more peak power. An aftermarket 110 LC cam will not sound stock. The "962" 350/350 (or L-82, same grind) cam will sound and act stock but will have a lot more top end if you get some better heads.

-Mark.
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Old Jun 26, 2007 | 04:19 PM
  #24  
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Originally Posted by foxymophandlpapa
Should I really be concerned about compression? Now I know the L-82 sports a 9:1, but if I could bump it up closer to 9.5:1... Is that possible with the stock components? I dont' ahve to worry about iron heads yet at 9.5:1 do I?
FYI - I am running 64cc Dart Iron Eagle heads and a steel shim gasket with the stock L-82 bottom end. This yields 10.4 C/R and it runs fine on pump premium. The modern chamber design helps as does the thin head gasket to keep the quench tight.

Your results may vary and you need to match the C/R to the cam timing.

-Mark.
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Old Jun 26, 2007 | 04:20 PM
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Thanks for all the info Mark. I guess when it gets time for cam selection, I'll be alot more knowledgeable. Maybe I'll just buy another block so I can do one hotrod, and one original!
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Old Jun 26, 2007 | 04:30 PM
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The stock GM L-82 cam will like more compression because it has a relatively late closing inlet valve. I wouldn't be afraid to run 10-10.25:1Personally, I'm running the "151" in my son's '76 and it's built with a static compression of 10.25:1 and it runs very strong on premium.
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Old Jun 26, 2007 | 06:01 PM
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Unless the 882 are in perfect shape and all you have to do is some bowl clean up and some $100 springs, they are the black sheep of the cylinder heads.
I just started my car with a the Comp Cams 470/270 cam and so far its pretty good sounding and I notice a power gain.
I got it idling about 600 in gear.
Stock I had about 18 lbs of vacuum now its down to 12.
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Old Jun 26, 2007 | 07:11 PM
  #28  
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Originally Posted by Tim H
Unless the 882 are in perfect shape and all you have to do is some bowl clean up and some $100 springs, they are the black sheep of the cylinder heads.
I just started my car with a the Comp Cams 470/270 cam and so far its pretty good sounding and I notice a power gain.
I got it idling about 600 in gear.
Stock I had about 18 lbs of vacuum now its down to 12.
As in perfect shape I assum you mean the iron. But wow Tim, you're the first person I've ever heard say anything quality about 882 heads. But I do understand alot of people's reasoning about dumping money into heads that won't match up to what you can buy. I guess it really is gonna depend on how much I want to keep it original. I mean I HAVE to put on headers, so maybe I will change out the heads. It just seems like my goal is not worth it. I guess to the shelf the 882's go
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Old Jun 26, 2007 | 08:40 PM
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Originally Posted by foxymophandlpapa
As in perfect shape I assum you mean the iron. But wow Tim, you're the first person I've ever heard say anything quality about 882 heads. But I do understand alot of people's reasoning about dumping money into heads that won't match up to what you can buy. I guess it really is gonna depend on how much I want to keep it original. I mean I HAVE to put on headers, so maybe I will change out the heads. It just seems like my goal is not worth it. I guess to the shelf the 882's go
Oh I don't like them either but, just tring to help you save money and stay original, myself I would go with Darts or Summit heads.
Unless your going with a real big cam or a roller set up, you don't anything over 175/180 CC.
All those $1000 and up iron heads are a waste of money on the street and only for bragging rights.
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Old Jun 26, 2007 | 09:29 PM
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Originally Posted by Tim H
Oh I don't like them either but, just tring to help you save money and stay original, myself I would go with Darts or Summit heads.
Unless your going with a real big cam or a roller set up, you don't anything over 175/180 CC.
All those $1000 and up iron heads are a waste of money on the street and only for bragging rights.
Ya, I would most likely go with the 180 Iron Eagle, 64 cc. They seem to be the best bang for the buck, and more towards the application I'm looking at. Problem is, I wouldn't be able to use the stock valve covers would I? Thats one thing I really can't stand are huge valve covers.

I do appreciate the help Tim, I think you're the only one who has stuck to my goal regardless the dislike for the 882s. Its good to get help on exactly what you want. Thanks alot.
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