L82 upgrade thread
Thread Starter
Melting Slicks
Joined: Oct 2011
Posts: 2,748
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From: Sacramento California
C2 of Year Finalist (performance mods) 2019
2018 C2 of Year Finalist
L82 upgrade thread
Started a new thread.
What started as a new exhaust project turned into a major top end overhaul. 78 Pace Car L82 Auto. Had a slight miss when I bought it. 35k actual miles, in very good condition. Replaced a burnt plug wire, but problem didnt go away. Finally pulled the valve cover and found a rocker arm totally off the valve, pushrod bent. Replaced pushrod, and it bent again. Pulled intake to check lifter, and found it locked solid.
Decided "while Im here" to go ahead and order a set of AFR 195cc heads, Perf RPM and some roller rockers. Going with a .015 head gasket for 10.25 compression. Not replacing cam at this time. If it decides to go, then Ill pull the motor and punch it to 383+.
Oh, and dont have your buddy pressure wash your intake manifold, or it will end up like this:
Factory 2.02 GM 882 heads:
Factory L82 Flat Top Pistons
What started as a new exhaust project turned into a major top end overhaul. 78 Pace Car L82 Auto. Had a slight miss when I bought it. 35k actual miles, in very good condition. Replaced a burnt plug wire, but problem didnt go away. Finally pulled the valve cover and found a rocker arm totally off the valve, pushrod bent. Replaced pushrod, and it bent again. Pulled intake to check lifter, and found it locked solid.
Decided "while Im here" to go ahead and order a set of AFR 195cc heads, Perf RPM and some roller rockers. Going with a .015 head gasket for 10.25 compression. Not replacing cam at this time. If it decides to go, then Ill pull the motor and punch it to 383+.
Oh, and dont have your buddy pressure wash your intake manifold, or it will end up like this:
Factory 2.02 GM 882 heads:
Factory L82 Flat Top Pistons
Safety Car
Joined: Mar 2007
Posts: 3,652
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From: Bridgewater nj
I would use eagle1 mag cleaner for cast aluminum rims. The one that has the warning not to use on clear coat.
Using a .015 head gasket is looking for trouble (leaks) on a well used motor. You're better off milling the head .010-.015 and use a .030 for better sealing.
Question, are those stock L82 pistons? It's been a long time since I've seen a stock one opened up...
Using a .015 head gasket is looking for trouble (leaks) on a well used motor. You're better off milling the head .010-.015 and use a .030 for better sealing.
Question, are those stock L82 pistons? It's been a long time since I've seen a stock one opened up...
Thread Starter
Melting Slicks
Joined: Oct 2011
Posts: 2,748
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From: Sacramento California
C2 of Year Finalist (performance mods) 2019
2018 C2 of Year Finalist
Well, I am assuming those are the stock pistons, although there was a felpro head gasket on it, so perhaps its had a rebuild.
The answer is Yes, stock pistons. No overbore. .025 deck height.
474190 High Performance Piston
This piston is for 71-80 L82. Piston OD 3.998 to 3.999". This 350 standard, pressed pin, high performance piston has a 9:1 compression ratio with 76cc head chamber volume (ID# 336747, 464664 or 464692).
The answer is Yes, stock pistons. No overbore. .025 deck height.
474190 High Performance Piston
This piston is for 71-80 L82. Piston OD 3.998 to 3.999". This 350 standard, pressed pin, high performance piston has a 9:1 compression ratio with 76cc head chamber volume (ID# 336747, 464664 or 464692).
Last edited by DucatiDon; Nov 29, 2012 at 07:55 PM.
Le Mans Master
Joined: Oct 2010
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From: melbourne florida
2023 C3 of the Year Finalist - Modified
doesn't look right to me. also just so you know you don't "punch" it to a 383. it requires both boring the block and installing a longer stroke crank . hopefully it works out nice project.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
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From: Las Vegas - Just stop perpetuating myths please.
L82 came with forged pistons.
Yes those are stock forged pistons as the L82 is easily modified for performance and can take it too. L82 had a good performance cam too but weak heads and smog tuned. I wouldn't be surpirzes if there is forged crank inside.
My only recommendation is if u run aluminum heads u need a good head gasket.
Do a google search as Aluminum heads don't like every MLS gasket. They seem to work better with a graphite head gasket and/or a deck finish of 25-30Ra (Rh?) - they need to slide around some. Nothing can be done with the block deck while still in the car but the head gasket can be optimized. Or u may want to stay with iron heads but the larger chamber will some power behind - less effective. I like my World Product Torquer II's - pocket ported with 67cc chambers but don't know what c.r. that will leave you with.
Good luck and thx for posting as i was wondering if my bad news diagnose was correct (or just painful).
cardo0
My only recommendation is if u run aluminum heads u need a good head gasket.
Do a google search as Aluminum heads don't like every MLS gasket. They seem to work better with a graphite head gasket and/or a deck finish of 25-30Ra (Rh?) - they need to slide around some. Nothing can be done with the block deck while still in the car but the head gasket can be optimized. Or u may want to stay with iron heads but the larger chamber will some power behind - less effective. I like my World Product Torquer II's - pocket ported with 67cc chambers but don't know what c.r. that will leave you with.Good luck and thx for posting as i was wondering if my bad news diagnose was correct (or just painful).
cardo0
Thread Starter
Melting Slicks
Joined: Oct 2011
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From: Sacramento California
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2018 C2 of Year Finalist
AFR recommends the Fel Pro 1003. Im going with the 1094 for perfect quench and a bump in compression. Ill take extra time cleaning and scotch brighting the block face prior to install.
Melting Slicks
Joined: May 2006
Posts: 2,590
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From: Nashville TN
St. Jude Donor '09
I'm using same gasket with my alum heads. I cleaned surface good with ScotchBrite on old L-48 block. Did 3 years ago and no leaks. Sounds like you'll have a nice setup when done; should put a big smile on your face.
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Thread Starter
Melting Slicks
Joined: Oct 2011
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From: Sacramento California
C2 of Year Finalist (performance mods) 2019
2018 C2 of Year Finalist
Ive run a thread tap through all the holes, scotch brite and sanded the deck face.
I hope to mock it up and fab the AC bracket prior to install. (HIgher ports means the bracket needs to be modified)
More pics to come.
I hope to mock it up and fab the AC bracket prior to install. (HIgher ports means the bracket needs to be modified)
More pics to come.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
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From: Las Vegas - Just stop perpetuating myths please.
You may a good idea here to finish the deck without machining.
Please post your results,
cardo0
Drifting
Joined: Sep 2010
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From: Laguna Niguel California
I'd suggest some more investigation into the lifter problem. Why did it happen? Is there an oiling problem? Is the cam OK at that location?
Good decision to upgrade from the old 882 heads. You'll be glad you did.
Good decision to upgrade from the old 882 heads. You'll be glad you did.
What cam did u choose?
Thread Starter
Melting Slicks
Joined: Oct 2011
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From: Sacramento California
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2018 C2 of Year Finalist
Went with a Howard Cams Hyd Roller 230 duration .50/.51 lift.
$200 cheaper than the Lunati.
Didnt want to chance the cam and having to do everything twice.
Next time it will be a 383 rebuild.......
Kinda want to do that to my 63 too.....
$200 cheaper than the Lunati.
Didnt want to chance the cam and having to do everything twice.
Next time it will be a 383 rebuild.......
Kinda want to do that to my 63 too.....
Last edited by DucatiDon; Dec 5, 2012 at 06:58 PM.
Thread Starter
Melting Slicks
Joined: Oct 2011
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From: Sacramento California
C2 of Year Finalist (performance mods) 2019
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Digging in to replace the cam....
No piston skirts or any other debris in the pan...Excellent!
Oil pan and fuel pump off...Balancer and front cover next...
No piston skirts or any other debris in the pan...Excellent!
Oil pan and fuel pump off...Balancer and front cover next...
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Forged crank?
Once u have the dampner off give the crank snoot a tap with a metal wrench. If u can hear it ring it means its a forged piece. Also a forged crank will have large parting lines down its length. Just nice to know what u have to work with.
Man with that much cam and those heads your gonn'a make some real power.
Good luck and post your results,
cardo0
Man with that much cam and those heads your gonn'a make some real power.
Good luck and post your results,
cardo0
Thread Starter
Melting Slicks
Joined: Oct 2011
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From: Sacramento California
C2 of Year Finalist (performance mods) 2019
2018 C2 of Year Finalist
And in case you wanted to know, Yes the radiator and hood must come off an AT/AC car to do a cam swap. I think its easier to pull the motor to do it btw.