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78 L82

Old 08-25-2005, 11:10 PM
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toupstrio
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Default 78 L82

Looking to rebuild my L82 350 would like to do it myself and come up with about 350HP can someone give me some good combos to use, Cam,Pistons Etc.
Old 08-26-2005, 12:24 AM
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Victor
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I'm rebuilding my '79 L-48 as we speak. I haven't narrowed down what I want to do with my bottom end yet, but I'm going to use one of the Trick Flow kits from Summit. See the link below. The kits include cylinder heads, cam, valvetrain, and gaskets and they claim they make between 350-500 HP and 400-450 TQ. Just make sure you have around a 10:1 compression ratio, an edelbrock Airgap intake, and a Holley 750 CFM carb like they said they did in the fine print

http://www.summitracing.com/catalogs...yaug/135f.html
Old 08-26-2005, 11:44 AM
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The Trick Flow kits are nice, but a little high priced for what ya get if you ask me.
Give the holley sysm. max kit a look over...more bang for the buck i think. but what ever you go with good luck!

Holley kit
Old 08-26-2005, 12:00 PM
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St. Jude Donor '08-'09

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What do you want to do with your car? Are you a dragger? autocrosser? show and shine with parades? cruiser? daily driver? Need to know this before you start.

Here's what i've learned from the forum:
The L82 cam you have now is a pretty good cam, with .450 lift (I can't remember what the duration is, I think around 220). What's really holding you back is heads, compression ratio and exhaust. If you're bottom is solid and your rings are good, you could go with the topend kit like was suggested by grayhook and victor. With new iron heads I'd keep the CR between 9.5 and 10 to keep using pump gas. With aluminum, many on the forum are running over 10 on pump gas. Heads are a tough choice, I'd think about getting something with more flow then stock, and larger intake and exhaust volumes. Velocity is just as important as volume, so unless you want to do some real high rpm racing (majority of time over 6000rpm) under 200cc seems to work well with the L82 cam for a street car. Headers are also a good way to make power, and true duals with no cats on a car like yours will do wonders. Tell us more about what you want, and we'll give you some more advice.

trw
Old 08-26-2005, 12:22 PM
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Default Agreed on Cam. Maybe add this

New Vortec heads ($500-$550), World Products Vtec intake ($150). If you have to go into the bottom end, then go to flat tops and keep it to 10.5:1 or less. If it's the L 82 cam, I think you will be on top of that 350 # you seek.
Old 08-26-2005, 02:11 PM
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SLVRSHRK
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Originally Posted by jackmoore
New Vortec heads ($500-$550), World Products Vtec intake ($150). If you have to go into the bottom end, then go to flat tops and keep it to 10.5:1 or less. If it's the L 82 cam, I think you will be on top of that 350 # you seek.
Doesn't the 78 L-82 already have flat top pistons? Believe they are forged as well.
Old 08-26-2005, 02:18 PM
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Forged flat-tops...
Old 08-26-2005, 03:59 PM
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Empatho
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get some Vortec heads get a 3 angle Valve job, cut heads for 2.02"/1.6" valves, a port polish job, and a edelbrock air-gap vortec intake, LT headers dual exhaust
Old 08-27-2005, 09:59 PM
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Thanks for all the help
Old 08-27-2005, 10:05 PM
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Default Just for fun

Originally Posted by 72 stingray owner
What do you want to do with your car? Are you a dragger? autocrosser? show and shine with parades? cruiser? daily driver? Need to know this before you start.

Here's what i've learned from the forum:
The L82 cam you have now is a pretty good cam, with .450 lift (I can't remember what the duration is, I think around 220). What's really holding you back is heads, compression ratio and exhaust. If you're bottom is solid and your rings are good, you could go with the topend kit like was suggested by grayhook and victor. With new iron heads I'd keep the CR between 9.5 and 10 to keep using pump gas. With aluminum, many on the forum are running over 10 on pump gas. Heads are a tough choice, I'd think about getting something with more flow then stock, and larger intake and exhaust volumes. Velocity is just as important as volume, so unless you want to do some real high rpm racing (majority of time over 6000rpm) under 200cc seems to work well with the L82 cam for a street car. Headers are also a good way to make power, and true duals with no cats on a car like yours will do wonders. Tell us more about what you want, and we'll give you some more advice.

trw
Just trying to get a little more out of her not racing and really dont need top end power. Also my rear wheels are leaning in at the top and tires wearing on inside do you think thats a rear spring or trailing arm problem?
Old 08-27-2005, 11:09 PM
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Originally Posted by Empatho
get some Vortec heads get a 3 angle Valve job, cut heads for 2.02"/1.6" valves, a port polish job, and a edelbrock air-gap vortec intake, LT headers dual exhaust
Empatho, are you running this combo?If so hows it working out? What carb would you use for this combo?Why the 3 angle valve job arent the vortec heads good as they are?
Old 08-28-2005, 12:25 AM
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Originally Posted by toupstrio
Just trying to get a little more out of her not racing and really dont need top end power. Also my rear wheels are leaning in at the top and tires wearing on inside do you think thats a rear spring or trailing arm problem?
I'm no expert, but that sound related to the trailing arms. I believe that trailing arms control the camber (angle of the tire) while the spring works more with how the tire travels up and down.

trw
Old 08-28-2005, 12:47 AM
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billlambeer
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Yeah, shims on trailing arms, which can sometimes be a pain will fix that, and possibly making the spring go up and down by tightening it up and loosening it. As far as heads etc. The vortec is a great choice, they will up your engine compression ratio. Make sure that you get the 64 cc fastburn ones, this will throw you around 10.5 or so. Im not 100% sure, but i believe that these heads are the same as the aluminum ones i have which means that you will have to get a whole new intake manifold also since they different. There are also issues with pushrods working right. So in the end, for getting those vortec heads, you have to get new head, a new manifold, special gaskets, special intake manifold bolts, guideplates, and new pushrods, which have to be hardened for the guideplates.

This may sound like alot of effort and time but i believe that you will like the improvement, while i dont know any difference really since i have not have another setup. I reasearched this for a long while and found that it was one of my best options.

Oh and dont change the pistons or cam, lots more effort if you dont know exactly what is going on, plus they are pretty good in your l82

Good luck
Matt

Last edited by billlambeer; 08-28-2005 at 12:52 AM.
Old 08-28-2005, 01:06 AM
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Retro78
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Originally Posted by toupstrio
Just trying to get a little more out of her not racing and really dont need top end power. Also my rear wheels are leaning in at the top and tires wearing on inside do you think thats a rear spring or trailing arm problem?
On your rear wheel camber issue...It could be that you just need an alignment but more than likely the root cause is worn 'side yokes' in the diff. This year of vette is known to NOT have hardened yokes and as a result they wear faster than normal. My 78 with only 70K had this problem big time. As the yokes wear they actually retract inside the diff. It does not take much movement of the yokes to cause a large change in rear negative camber(leaning in). Another symptom is clunking while going over bumps as the yokes move in they bang against the center shaft inside the diff. When it gets really bad they start eating into the case of the diff...which is not a good thing. Put the back of your vette on jack stands(securely) and see how much movement you get in the yokes(in and out) as you have someone pull and push on the top of the rear wheeks. But the best way to measure this is to drop the half shafts and check the end play. I do not recall how much play is acceptable but others on this forum would. If you are over spec fix this first before doing power mods....you need a solid rear end that is well planted on the ground and with safe handling. If you do have a lot of yoke end play you should really rebuild/go through the entire diff at the same time you replace the yokes with hardened ones...then get an alignment. Member gtr999 is a specialist in this area and can also rebuild the diff for you if you want....he does top notch work. Sorry...but leaning of rear tires is most likely a symptom of larger issues that you cannot ignor on this model year.

Last edited by Retro78; 08-28-2005 at 01:42 AM.
Old 08-28-2005, 01:08 AM
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[QUOTE=billlambeer]Yeah, shims on trailing arms, which can sometimes be a pain will fix that, and possibly making the spring go up and down by tightening it up and loosening it.

NO!!!! The TA shims have nothing todo with camber at all...those shims are for tracking and toe adjustments. The camber adjustment is done at the strut rods. But as per my post above he likely has a problem with the side yokes that needs to be fixed first. No use adjusting camber(alignment) until the reason for it being out is resolved.

Last edited by Retro78; 08-28-2005 at 01:37 AM.
Old 08-28-2005, 01:43 AM
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Empatho
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Originally Posted by bozzman3
Empatho, are you running this combo?If so hows it working out? What carb would you use for this combo?Why the 3 angle valve job arent the vortec heads good as they are?
I'm using a Q-jet with the edelbrock performer rpm intake manifold for the vortec heads, I have the 3 angle valve job because I wanted the most out of the heads, I'm going to take this combo off and put it on my 383 that is waiting for me in Cali its going to be a beast
Old 08-28-2005, 01:49 AM
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I hope I get in the high tens with that combo a shot of nitrous and the lighter Vette

Last edited by Empatho; 08-28-2005 at 02:13 AM.

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Old 08-28-2005, 04:09 AM
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But the best way to measure this is to drop the half shafts and check the end play. I do not recall how much play is acceptable but others on this forum would.
i dunno if this is the official specs but but i got advice (Big-G on this forum) to change my yokes because the they end play is >.020


art-corvette
Old 08-28-2005, 03:05 PM
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Originally Posted by Empatho
I'm using a Q-jet with the edelbrock performer rpm intake manifold for the vortec heads, I have the 3 angle valve job because I wanted the most out of the heads, I'm going to take this combo off and put it on my 383 that is waiting for me in Cali its going to be a beast
One last question did this set up fit under the stock hood?
Old 08-29-2005, 12:21 AM
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Originally Posted by bozzman3
One last question did this set up fit under the stock hood?
yes it fits on my 78


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