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More power to a 1978 L82

A

aremar2

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Hi. Then it is time to get a little more power out of the L82. Motor is original and has 22.00 miles on it, undercarriage is upgraded to stage 2. Original exhaust is still on the car, stamped 1978, no rust, so I assume the miles are honest.
(Pace car, garaged for the last 15 years).

This is what I have thought of: Headers with 2,5 " collectors, Pypes 2,5 " racing X-pipe exhaust, Comp.cam high energy 268 cam, roller rockers, edelbrock performer intake non EGR. Get rid of the AIR, riser and EGR.

Norway have no emmission control for these vehicles, so I just want what getting the most power without changing or machining the heads.

Any comments, advices etc???:W
 

Glensgages

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..... without changing/machining the heads, that's about as-much power as you can get out of the L-82 (I'd guess ):
it's possible that the RPM Air Gap intake and a 650 cfm Holley double-pump carb would provide even-better performance, if you aren't adverse to swapping carbs, but I'm thinking the OEM heads will be the bottle-neck to future performance gains.
 
A

aremar2

Guest
..... without changing/machining the heads, that's about as-much power as you can get out of the L-82 (I'd guess ):
it's possible that the RPM Air Gap intake and a 650 cfm Holley double-pump carb would provide even-better performance, if you aren't adverse to swapping carbs, but I'm thinking the OEM heads will be the bottle-neck to future performance gains.

Ok, I thought so. Tried to change the cfm flow to 650 in the Comp.Cam simulation program, but didn´t gain more than 2 hp.
So in this matter I think it´s better to keep the Q-jet as long as it works o.k.
Thanks for your answer. :)
 

Glensgages

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Ok, I thought so. Tried to change the cfm flow to 650 in the Comp.Cam simulation program, but didn´t gain more than 2 hp.
So in this matter I think it´s better to keep the Q-jet as long as it works o.k.
Thanks for your answer. :)

..... in the early-'80s, we used the existing LM-1 short-block from my '79 Z28, and added a simialr cam, intake, headers & exhaust, etc., as you are contemplating:
while we didn't have dyno-sims back-then, the car performed better (verified repeatedly at the drag-strip ) using a 650 double-pumper than with a Q-Jet.....

Is it possible the 'puter is giving you 'bulk-numbers', without considering throttle-response?
;shrug
 

Vette79

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As Glen said your heads will be the bottleneck. Upgrading your exhaust and installing headers is a very good idea IMO. Keep your Q-jet and have it tuned. If you install anything else other then an Edlebrock Performer Intake you possibly will encounter clearance issues with hood and air cleaner. Go with the CompCam XE 268H Cam and Lifter Kit. It comes with everything you need. Remove the emmissions components if you don't want it. This spring I am actually replacing my intake, cam, lifters, springs, pushrods, waterpump, pulley's, timing chain, fuel pump, roller rockers, gaskets and bolts. So, I'll be able to provide more feedback and any performance gains when project complete. I want to install new heads but they can be expensive and I only have so much to work with. I'll have to wait till later to install these.
 

Glensgages

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If you install anything else other then an Edlebrock Performer Intake you possibly will encounter clearance issues with hood and air cleaner.

..... although the '07 Edelbrock catalog states it won't fit stock Corvette hood-profiles, last year a buddy put the RPM vortec Air Gap (carb pad height 4.720" ) under the hood of his '80 Corvette successfully, using a Holley carb (had he used an adaptor-plate and his Q-Jet, it is questionable if it'd fit ), and it appears the '80-'82 hood is even-lower than the pre-'79 hood profile:
the carb pad height of non-vortec Edelbrock intakes is 4.270" for Performer EPS (# 2701 ), 4.050" for Performer (2101 ), 4.320" for Performer Air Gap (2601 ), 4.720" for RPM Air Gap (7501 ), Performer RPM (7101 ), and Performer RPM Q-Jet (7104 )
 
A

aremar2

Guest
..... in the early-'80s, we used the existing LM-1 short-block from my '79 Z28, and added a simialr cam, intake, headers & exhaust, etc., as you are contemplating:
while we didn't have dyno-sims back-then, the car performed better (verified repeatedly at the drag-strip ) using a 650 double-pumper than with a Q-Jet.....

Is it possible the 'puter is giving you 'bulk-numbers', without considering throttle-response?
;shrug

Yes, that´s a possibility. The program is most likeky made to sell cams, not carburetors. Think I will keep the Q-jet and use the money on some Bilsteins.
Thanks for your respons.
 

Glensgages

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..... think I will keep the Q-jet.....
:beer

I'd choose an intake that will allow you to use the Q-Jet without having to use an adaptor-plate, which may casue fitment issues with your stock hood.
;)
 
A

aremar2

Guest
O.k. - I´v seen that kit, it seems to be a good solution, think I will go for that, will do pretty much the same as you. Looking forward to hear from your project.
 

Vette79

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:beer

I'd choose an intake that will allow you to use the Q-Jet without having to use an adaptor-plate, which may casue fitment issues with your stock hood.
;)
Edlebrock Performer Intake will work out nicely then...;)
 

Hib Halverson

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71 04 12 19
Hi. Then it is time to get a little more power out of the L82. Motor is original and has 22.00 miles on it, undercarriage is upgraded to stage 2. Original exhaust is still on the car, stamped 1978, no rust, so I assume the miles are honest.
(Pace car, garaged for the last 15 years).

This is what I have thought of: Headers with 2,5 " collectors, Pypes 2,5 " racing X-pipe exhaust, Comp.cam high energy 268 cam, roller rockers, edelbrock performer intake non EGR. Get rid of the AIR, riser and EGR.

Norway have no emmission control for these vehicles, so I just want what getting the most power without changing or machining the heads.

Any comments, advices etc???:W

Elsewhere in this thread, there's a discussion of hood clearance. Before I'd make any decisions on cam and induction, I'd resolve the question of whether or not the Performer RPM (or RPM Air Gap) will "fit". Understand that "fit" means you can get the manifold, carb and air filter assembly under the hood without compromising performance and that means you need to have a big enough filter, the air cleaner top needs to have space between it and the carb's air horn and the air filter base can't sit too low on the carb. Based on my experience, the RPM will not fit your car unless you make some significant compromises in air filtering which will negate some of the Performer RPM's advantages at WOT and high rpm. If you want a powerful, relatively high rpm L82, then put a different hood on the car.

Unless you're budget-constrained, avoid a flat-tappet hydraulic cam. It's 50 year old technology that cam companies, today, still sell because they need some cheap entry level products.

That engine will perform far better if you install a short duration hydraulic roller along with appropriate valve springs. The difference, especially in the mid-range, will be significant. Also, as far as brands go, I think Crane holds the high-ground right now as far as quality. You can't go wrong with a Crane hyd. roller, a set of Crane dual valve springs, lifters and good pushrods.

As for roller rockers, again, the best in the business are Crane's Gold Race Rockers. The reason is Crane's "Quick-Lift" design. Comp really doesn't have anything like that. To understand the advantage of "Quick-Lift" it's best to read Crane's web site.

You combine the exhaust mods you've planned with some head work, add the Crane roller, the Performer RPM and a Holley of about 750 cfm and, provided it's assembled and tuned well, you're looking at 425hp at least!
 

minifridge1138

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Messages
908
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1982 Black Fastback
I put a Holley Street Dominator and Holley 600 cfm carburetor on my 1982 and have no problem with hood clearance (but i'm close).

However there is not room for a spacer/adapter so make sure you buy a manifold that will work with your Carb.

Good Luck and have fun!
 
A

aremar2

Guest
:beer

I'd choose an intake that will allow you to use the Q-Jet without having to use an adaptor-plate, which may casue fitment issues with your stock hood.
;)

Yes, seems like the performer intake is a bolt-on for Q-jet. Got to keep the original hood on this pace car, in case I want to sell it. Consider to look for another vette, more like a project car for the power play. Hunted in the beginning for a BB, but due to the curvy roads here in northern Norway it ended up with a small block. Thanks for your advice. :D
 
A

aremar2

Guest
Elsewhere in this thread, there's a discussion of hood clearance. Before I'd make any decisions on cam and induction, I'd resolve the question of whether or not the Performer RPM (or RPM Air Gap) will "fit". Understand that "fit" means you can get the manifold, carb and air filter assembly under the hood without compromising performance and that means you need to have a big enough filter, the air cleaner top needs to have space between it and the carb's air horn and the air filter base can't sit too low on the carb. Based on my experience, the RPM will not fit your car unless you make some significant compromises in air filtering which will negate some of the Performer RPM's advantages at WOT and high rpm. If you want a powerful, relatively high rpm L82, then put a different hood on the car.

Unless you're budget-constrained, avoid a flat-tappet hydraulic cam. It's 50 year old technology that cam companies, today, still sell because they need some cheap entry level products.

That engine will perform far better if you install a short duration hydraulic roller along with appropriate valve springs. The difference, especially in the mid-range, will be significant. Also, as far as brands go, I think Crane holds the high-ground right now as far as quality. You can't go wrong with a Crane hyd. roller, a set of Crane dual valve springs, lifters and good pushrods.

As for roller rockers, again, the best in the business are Crane's Gold Race Rockers. The reason is Crane's "Quick-Lift" design. Comp really doesn't have anything like that. To understand the advantage of "Quick-Lift" it's best to read Crane's web site.

You combine the exhaust mods you've planned with some head work, add the Crane roller, the Performer RPM and a Holley of about 750 cfm and, provided it's assembled and tuned well, you're looking at 425hp at least!


O.k., I´m new to this game, so thank you. I´l seach the internet looking for that parts. So that silly question: what is the difference between a flat tapped cam and a roller - see it is a significant difference in price, but what else? :eyerole
 

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