L82
Le Mans Master
Joined: Mar 2004
Posts: 7,458
Likes: 1,484
From: Little Rock AR
Originally Posted by MrSharky
Is the Engine Block in an '80, L82 a 4-Bolt Main and is the Crank Steel or is the Block and Crank the same as what is in the L48?
Thanks
Thanks
All forged bottom end with 4 bolt main and windage tray on L-82.
Cast pistons, cast crank, forged rods, 2 bolt main and no windage tray on L-48.
-Mark.
Thread Starter
Pro
Joined: Feb 2005
Posts: 568
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From: South Bend IN
Build
Would it be safe to assume that if I buy a low mile '80, L82 (4speed) with a solid stock bottom end, I can spend my upgrade money on Heads, Intake/Carb., Cam, Ignition, Exhaust and Rear End and get about 400 RWH? (180 more horses than stock)
I'm also thinking that it may be easier to start with a C4 in the form of a LT4 and just do Lid, Cam, Rollers/Springs, Exhaust and Rear End. That should be about 425 RWH for about the same cost. (105 more horses than stock)
Or am I being unrealistic in both cases?
Talk to me fellows.
I'm also thinking that it may be easier to start with a C4 in the form of a LT4 and just do Lid, Cam, Rollers/Springs, Exhaust and Rear End. That should be about 425 RWH for about the same cost. (105 more horses than stock)
Or am I being unrealistic in both cases?
Talk to me fellows.
Le Mans Master
Joined: Jun 2004
Posts: 9,289
Likes: 16
From: Skippack PA
St Jude Donor '13
Originally Posted by MrSharky
Would it be safe to assume that if I buy a low mile '80, L82 (4speed) with a solid stock bottom end, I can spend my upgrade money on Heads, Intake/Carb., Cam, Ignition, Exhaust and Rear End and get about 400 RWH? (180 more horses than stock)
I'm also thinking that it may be easier to start with a C4 in the form of a LT4 and just do Lid, Cam, Rollers/Springs, Exhaust and Rear End. That should be about 425 RWH for about the same cost. (105 more horses than stock)
Or am I being unrealistic in both cases?
Talk to me fellows.
I'm also thinking that it may be easier to start with a C4 in the form of a LT4 and just do Lid, Cam, Rollers/Springs, Exhaust and Rear End. That should be about 425 RWH for about the same cost. (105 more horses than stock)
Or am I being unrealistic in both cases?
Talk to me fellows.
I'm thinking if 400 at the rear wheels is your aim.. just building the top of the motor up may be asking for trouble down low. However I'm hardly an expert so I will
to other responses.
Thread Starter
Pro
Joined: Feb 2005
Posts: 568
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From: South Bend IN
Originally Posted by page62
400 horses could potentially tear up the drivetrain...
Could you be more specific? Do you mean Transmission and Rear End or Bottom End or something completely different?
I know that if I just build up the Engine then the Transmission and Rear End become the weakest links. However, I plan to start with a 4speed car, change out the Joints and Rear End. The drive shaft should still be in good shape on a low mileage car but even brand new parts could break under the wrong conditions.
Last edited by MrSharky; Mar 22, 2005 at 08:04 PM.
Le Mans Master
Joined: Mar 2002
Posts: 7,456
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From: Coming home from Luckenbach Texas
The transmission and engine bottom end would like stand up to 400 hp. (But 400 rwhp is an unrealistic figure...set a goal for 400 flywheel hp -- at least if you want a streetable car).
I'm not so sure about the Dana 44 rear axle and the lightweight half-shafts, however...they're the weakest links.
I'm not so sure about the Dana 44 rear axle and the lightweight half-shafts, however...they're the weakest links.
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Thread Starter
Pro
Joined: Feb 2005
Posts: 568
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From: South Bend IN
Originally Posted by page62
The transmission and engine bottom end would like stand up to 400 hp. (But 400 rwhp is an unrealistic figure...set a goal for 400 flywheel hp -- at least if you want a streetable car).
I'm not so sure about the Dana 44 rear axle and the lightweight half-shafts, however...they're the weakest links.
I'm not so sure about the Dana 44 rear axle and the lightweight half-shafts, however...they're the weakest links.
Anyone else care to chime in?
Le Mans Master
Joined: Mar 2004
Posts: 7,458
Likes: 1,484
From: Little Rock AR
Originally Posted by TheKomoman
I have an '80 L-82 with 51k and advice I've gathered from this forum tells me it's ok to build the top up without rebuilding the bottom, at least to a point. My goals are somewhat more modest than yours, however. I plan to build more for torque and lower RPM HP. My basic plan is for Dart Iron Eagles 180/64's, Comp 268H, Dynomax headers, rebuild the Q-Jet, advance the ignition curve and replace the odds and ends of that build (timing gear & chain, push rods, etc). I'm hoping this will put me into the 325 or so range.
I'm thinking if 400 at the rear wheels is your aim.. just building the top of the motor up may be asking for trouble down low. However I'm hardly an expert so I will to other responses.
I'm thinking if 400 at the rear wheels is your aim.. just building the top of the motor up may be asking for trouble down low. However I'm hardly an expert so I will
to other responses.
-Mark.
Le Mans Master
Joined: Jun 2004
Posts: 9,289
Likes: 16
From: Skippack PA
St Jude Donor '13
Originally Posted by stingr69
I hate to sound like your mother but that is probably too much compression for that cam. You will be at 10.4:1 with a thin gasket and those 64cc heads. I am running my 80 L-82 with Dart IE heads and 64cc chambers but I have more duration than the 268H so I do not have problems with detonation. If I were you, I would be looking for bigger chambers or bigger cam timing one way or the other. Call Comp and ask them to see what they say. I bet you they steer you to a Magnum 270H (or bigger)
-Mark.
-Mark.
I've seen several guys mention the stock L-82 cam is a good all around cam and a couple of guys that have left it in and used those Dart heads. But then I've had other folks tell me that as long as I have the engine torn down that far I may as well take advantage of modern cam technology......
Last edited by TheKomoman; Mar 22, 2005 at 09:04 PM.
Le Mans Master
Joined: Mar 2004
Posts: 7,458
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From: Little Rock AR
(sorry for the hijack guys :o )
Komo,
Modern cam technology can work. You just need to match the cam to the combo. I run the L-82 cam with my combo and it gets the job done quite nicely. Lots of people find it suprizing to hear that I can run pump gas with a stock cam and 10.4 C/R but thats what I am doing here and it works great.
The 268H was designed to work with 8:1 static compression ratio and up to maybe around 9:1 static compression ratio engines. Yours will be quite a bit higher at around 10.4 C/R. As I said before, the 270H would work with that much compression as would other cams with later exhaust valve closing points but the 268H is too small in my opinion and will likely detonate on pump gas. Not a desireable situation.
-Mark.
Komo,
Modern cam technology can work. You just need to match the cam to the combo. I run the L-82 cam with my combo and it gets the job done quite nicely. Lots of people find it suprizing to hear that I can run pump gas with a stock cam and 10.4 C/R but thats what I am doing here and it works great.
The 268H was designed to work with 8:1 static compression ratio and up to maybe around 9:1 static compression ratio engines. Yours will be quite a bit higher at around 10.4 C/R. As I said before, the 270H would work with that much compression as would other cams with later exhaust valve closing points but the 268H is too small in my opinion and will likely detonate on pump gas. Not a desireable situation.
-Mark.
Melting Slicks
Joined: Dec 2000
Posts: 2,198
Likes: 2
From: Eastern Connecticut
If you want to stay around 268 duration, try the Crane PowerMax cam, it's ground on a 112 degree LSA so it likes more compression. Also, is the Dart 64 or 67cc? That'll give you more like 10:1 with flattops, less if they are in the hole like mine. There are lots of different head gaskets to fine-tune the compression ratio, too. Joe
PowerMax H-268-2 (replaces H-272-2), Good idle, daily usage and off road, towing, performance and fuel efficiency, 2600-3000 cruise RPM, 8.75 to 10.75 compression ratio advised. Basic RPM 2000-5000 218/230@.050; .459/.486 lift; 112°lobe sep.
PowerMax H-268-2 (replaces H-272-2), Good idle, daily usage and off road, towing, performance and fuel efficiency, 2600-3000 cruise RPM, 8.75 to 10.75 compression ratio advised. Basic RPM 2000-5000 218/230@.050; .459/.486 lift; 112°lobe sep.
Le Mans Master
Joined: Jun 2004
Posts: 9,289
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From: Skippack PA
St Jude Donor '13
Originally Posted by stingr69
(sorry for the hijack guys :o )
Komo,
Modern cam technology can work. You just need to match the cam to the combo. I run the L-82 cam with my combo and it gets the job done quite nicely. Lots of people find it suprizing to hear that I can run pump gas with a stock cam and 10.4 C/R but thats what I am doing here and it works great.
The 268H was designed to work with 8:1 static compression ratio and up to maybe around 9:1 static compression ratio engines. Yours will be quite a bit higher at around 10.4 C/R. As I said before, the 270H would work with that much compression as would other cams with later exhaust valve closing points but the 268H is too small in my opinion and will likely detonate on pump gas. Not a desireable situation.
-Mark.
Komo,
Modern cam technology can work. You just need to match the cam to the combo. I run the L-82 cam with my combo and it gets the job done quite nicely. Lots of people find it suprizing to hear that I can run pump gas with a stock cam and 10.4 C/R but thats what I am doing here and it works great.
The 268H was designed to work with 8:1 static compression ratio and up to maybe around 9:1 static compression ratio engines. Yours will be quite a bit higher at around 10.4 C/R. As I said before, the 270H would work with that much compression as would other cams with later exhaust valve closing points but the 268H is too small in my opinion and will likely detonate on pump gas. Not a desireable situation.
-Mark.
Tell me if I'm wrong MrSharky....Thanks to both Joe & Mark here.. and I hope you both chime back in.
I hadn't seen where the Dart heads would jump the compression up that much. I'm much more interested in a result than I am in replacing parts that I don't need to. What I'm aiming for is a mild street performer that runs well in the RPM midrange. That's why I thought the 180/64 (Joe yes the Darts are 64, they come in 64 & 72 in the Iron Eagles) was the right combo. Alot of guys have used that 268 and what I'd read made it sound like it was in the right neighborhood for me too. Obviously I still have a lot of reading to do.
I will be giving Dart, Comp and Crane calls to see what they have to recommend for my purposes but I'm very interested in both of your experiences. If the L-82 cam and those heads are the combo to give me what I'm looking for I'm perfectly content with not replacing it. I know the heads are the real choker of the L-82 anyway.
Still
Le Mans Master
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From: Coming home from Luckenbach Texas
The L82 cam is the same one that was used in the 350/350 engine of the late 60's. I'm using it -- and the rest of the stock L82 bottom end -- with the Summit/Dart IE 165/67 "fuelie" heads. Needless to say, the car is now wicked fast...and I learned yesterday I can lay down a pretty good patch of rubber in 2nd gear 
Le Mans Master
Joined: Jun 2004
Posts: 9,289
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From: Skippack PA
St Jude Donor '13
Something of a self-serving TTT here.. but interesting info as well. I submitted a question to Dart via their web site(recently very much improved). I gave them the basic idea of what I wanted to do and this was their response:
Confirmation of your comments straight from the horse's mouth, page62! 
I'm a little stunned that they suggested I spend less money, but I'm happy about it!
Your best bet would be to look at our Iron Eagle S/S line of heads, you can get these through Summit they offer them in their own private label. These heads have been used on engines making up to 400 horsepower and all below 5000 rpm. Thanks
I'm a little stunned that they suggested I spend less money, but I'm happy about it!
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by MrSharky
Anyone else care to chime in?
The C-3 iron rearends are pretty tough once you install good yokes
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Joined: Feb 2005
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From: South Bend IN
Originally Posted by gkull
The L-82 stock bottom end is just about bullet proof. I installed various cams/heads/intakes and flat top pistons with a .030 over. In h-flat cams it probably exceeded 400 crank hp and could exceed 7000 rpm on a daily basis.
The C-3 iron rearends are pretty tough once you install good yokes
The C-3 iron rearends are pretty tough once you install good yokes
Thread Starter
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Joined: Feb 2005
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From: South Bend IN
Good information, as always.
Thanks guys, I’m now sure that the bottom end of a low mile L82 with a professionally built top end and drive train can make and take 400 RWH with the right cam, heads, intake, exhaust and gears.