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First time owner wants a bit more speed

 
Old 03-14-2019, 10:01 PM
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Thor79
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Default First time owner wants a bit more speed

Hey everyone,

I'm 21 and I just bought my first Corvette. It's a nice red '79 with the L82. I've always loved the C3 so I'm having a ton of fun fixing her up. Since I'm still in college, I couldn't buy the nicest one, but she run quite well. I just want a bit more HP. So I was wondering, what is the least expensive way to get it closer to 300 HP or so? I dont need anything crazy like a 700HP car, I just want a bit more than it currently has and I dont know what would be the most cost effective way to get north of 300HP. Any advice is helpful.
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Old 03-14-2019, 11:00 PM
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kossuth
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Well, thats kinda a loaded question. I gotta ask you a few questions before hand so we know exactly what we are dealing with.
1. Is the car running well currently? IE your choke isn't sticking on the carb, your timing is set as it's supposed to be etc etc?
2. Does your car HAVE TO retain the OEM emissions equipment by law to be legal?

While I'm not an expert on these cars obviously if the motor is out of tune, the timing off, or the carb being out of adjustment will cause performance issues. If that's all in order and your allowed BY LAW getting that old restrictive converter, the airpump and all that associated equipment off the car will un-clutter the engine compartment and help the old girl breathe. Installing a decent full dual exhaust with an X pipe would help as well. NOTE: You'll probably need to adjust the carb and such if you get it breathing out the exhaust better. Unless you purchase a new intake manifold you would also need to get a blockoff plate for the EGR. That would run about $20 or so. You would also need to block the airpump tubes in the manifolds as well. Probably also right in that $20 range. There might be a few other things you would need that I'm not thinking of but it shouldn't cost you much. You won't get anywhere near 300 HP but those items themselves would wake the old girl up some and I would use that as a baseline of where I would want to go next. Yeah headers and an aftermarket intake manifold will help quite a bit but you'll get alot more money into the car at that point and being you mention the car needs alot of work in other places I would make sure it runs well without pulling a valvecover.

If you have to 100% retain the emissions equipment you're gonna have to be alot more creative and it's gonna cost more.

Last edited by kossuth; 03-14-2019 at 11:21 PM.
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Old 03-14-2019, 11:03 PM
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Are you after a number, or a specific performance goal?

The cheapest way to make your car feel faster is to tune it. There are dozens of threads on this forum (several active right now). Look for posts by "Lars", and email him (don't PM) for his timing papers, and quadrajet tuning papers.

The other cheap way to make your car feel faster is to fix any suspension and steering issues. Make sure your tires are new.

I did all this on my 79, and it transformed the car (the Borgeson steering was the biggest improvement).

Other than that, how much do you want to spend? There are a few bolt on mods you can do for cheap (headers, for example). Beyond that, you'll probably want to make sure your engine is up to the challenge before bolting on new heads at great expense.
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Old 03-15-2019, 12:00 AM
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First thing you need to do is set a budget and stick to it. While I was in college I slowly built a 318 in my rusted out dodge half ton. Spent a few thousand I shouldn't have to do it but it was fun.

Also consider the rest of the drivetrain when driving after you've built the motor.

I didn't, just beat the snot out of the old truck till one day the tranny locked up and broke the bellhousing while I was rolling down the highway at 80. Fortunately the distributor wedged into the firewall and the motor never hit the pavement. I didn't have a ride after that. No money left.
Anyway,

Here's the easiest way.

https://www.summitracing.com/parts/edl-2038/?rrec=true

You can scrounge craigslist for used heads, intake, can, and carb but be sure to;

1) check out the parts real good before buying. Everyone who's been wrenching for any time has been overzealous and bought some junk.

2)take into account total cost (gaskets, carb kit, etc). Little parts add up real fast.

3) pay close attention to what you buy. Aluminum heads are not all created equal as an example.

Or, find a local shop who can do some porting to your current stuff and call your favorite cam company tell them what your goals are and ask for a cam recommendation. You may need to find different factory heads and/or intake to make porting worthwhile. I've never cared much about numbers matching so can't give you any advice on the potential for stock parts.
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Old 03-15-2019, 12:06 AM
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7T1vette
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You're not going to like this, but I can still remember being your age and wanting more power in my car.

My advice: Enjoy the car you have. Tune it the best it can be. Leave the BIG power for a little later....until you realize what risks you run with a powerful car.

At this point in time you need "wisdom", not more testosterone. (You'll thank me 10 years from now.)
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Old 03-15-2019, 12:16 AM
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Simple way to get some improved performance:
Intake, just make sure it will fit under your stock hood with a drop base air cleaner,
Headers with a good exhaust system,
HEI ignition, unless you want to keep the points and can set them,
And if it has the original Q-Jet, send it to Lars for a rebuild, if not get a Holley, bolt everything on over a weekend and enjoy.
By the way, we always need pictures and I don’t see any in this thread “YET”!

Last edited by OldCarBum; 03-15-2019 at 12:19 AM.
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Old 03-15-2019, 12:38 AM
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coletrickle35
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300 horsepower that is a very interesting threshold. 300 horsepower on up things can go very wrong very quickly. Anyone can jump in a 100- 200 horsepower car and romp it stomp it whip it drive like a maniac without losing control . I crashed a 280 horsepower 68AMX javelin and crashed a 290 HP 74 Nova in the same week when I was 16. Had a really bad crash in a 300 horsepower 76 Camaro before I had any respect or broken bones. My advice is to fix the Corvette up real nice and enjoy it when you get some money ahead and can afford to lose a car go over 300 horsepower

Last edited by coletrickle35; 03-15-2019 at 12:39 AM. Reason: Misspelling
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Old 03-15-2019, 10:35 AM
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Publish approximately WHERE the car is registered ... that "where" jurisdiction-law controls whether or not you CAN modify car. Your State is plenty close enough.

On a 200-300 hp sbc, changing intake manifold is Not gonna make much difference; and L82 intake is a decent piece to start with.

Carb & Distributor setup is Paramount! ... and will yield most bang-for-the-buck ... that IS THE starting point for anything else.

Contact CF member Lars; he has great Carb reputation. IIRC, same for Distributor.
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Old 03-15-2019, 12:04 PM
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Originally Posted by jackson View Post
Publish approximately WHERE the car is registered ... that "where" jurisdiction-law controls whether or not you CAN modify car. Your State is plenty close enough.

On a 200-300 hp sbc, changing intake manifold is Not gonna make much difference; and L82 intake is a decent piece to start with.

Carb & Distributor setup is Paramount! ... and will yield most bang-for-the-buck ... that IS THE starting point for anything else.

Contact CF member Lars; he has great Carb reputation. IIRC, same for Distributor.
I agree. Tuning the carb and ignition for performance is the first step in unleashing the potential of the L82. It has a respectable cam close in grind to the L46 "350/350HP" cam. I found that removing all of the emissions sensors helped a lot. However, if you are subject to emissions laws/inspections, then you may be limited in how much you can get away with.

Back when Florida had inspections, I was able to install a 3-way catalytic converter that addressed the increase in NOx from my blocking off/removing the EGR, EFE and thermal sensors in the intake. Once they ended inspections, I went true dual exhaust with H-pipe connecting L & R exhaust pipes and never looked back. I had the P/N 68301 Hedman Headers with the A.I.R. tubes and just capped the A.I.R. inlets when I boxed up the A.I.R. pump, hoses and brackets. I had the 68301's Jet Hot coated before Hedman had the HTC coated headers.

At the age of your vette, a fresh set of vacuum lines for your PCV, EVAP, Distributor advance, brake booster, headlights and cruise control will also resolve many gremlins related to deterioration in the vacuum system (the rubber hoses and the plastic connectors). Doc Rebuild is THE source for replacement vacuum hose kits.

Then, open the exhaust (headers, duals, free flowing turbo mufflers). I added a K&N filter. See my signature for a sampling of the mods I've made in the 22 years I have had my '80 L48.

Last edited by TedH; 03-15-2019 at 12:12 PM.
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Old 03-15-2019, 01:11 PM
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Originally Posted by jackson View Post
Distributor setup is Paramount! ... and will yield most bang-for-the-buck ... that IS THE starting point for anything else.
Take Jackson's advice!
Here's a how-to on setting up your distributor and adjusting your timing:
https://www.corvetteforum.com/forums...long-post.html
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Old 03-15-2019, 06:07 PM
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A 79 is underpowered for a Corvette. Get ignition and carb right it is still a corvette. It is gonna make you spend money on it anyway. Don't rush in to alterations.
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Old 03-15-2019, 08:33 PM
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REELAV8R
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In order of cheapest to more expensive but still cheap.

new gapped plug in heat range 5 for ngk

recurve the ignition

hook up vacuum advance to manifold vacuum. Use lars’ papers to get this right.

remove air pump

remove all emissions eqipment including disabling heat riser in right side manifold.

get cliff ruggles’ book off amazon on the quadrajet and read it at least three times then rebuild your carb using one of his rebuild kits. Or pay Lars to do it for you.

replace the 2 to 1 to 2 exhaust with true dual exhaust eliminating the antique caylitic converter.

owning a car like this it is pretty much a MUST to learn how to work on it unless you have deep pockets and then you’ll just be paying a lot to have some else screw stuff up.

oh and you can replace the stock clutch fan with a good electric fan set up if you want to free up a bit of hp to the wheels.

Last edited by REELAV8R; 03-15-2019 at 08:36 PM.
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Old 03-15-2019, 08:47 PM
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Quickest and easiest, most fun, and best bang for the buck......wait for it..... nitrous. Keep it at 100 hp or below and your biggest problem will be wearing out rear tires and running out of laughing gas. JMHO
Oh, and maybe speeding tickets.

Last edited by platinummaker; 03-15-2019 at 08:51 PM.
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Old 03-15-2019, 10:10 PM
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Heads, then cam, then intake. heads that flow better and a smaller head volume to increase compression with the pistons you have. Breathing easier increases HP , so does compression. More power from a more compressed bang.

Next is a bigger cam. with a bigger cam, your stuffing more sir/fuel into that cylinder for the bang. even a lower compression motor will benefit from more breathing.

Last would be a better intake. The L79 had a cast intake and still made over 350hp with a hydraulic lifter, solid lifter was 365hp.

Heads are the single biggest improvement but are very expensive for aluminum. Look for some used vortec heads and an intake that will bolt to it.

Look up Engine Masters on you tube or Motrtrend on Demand. they have a couple of episodes on low bunch chevy builds
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Old 03-16-2019, 09:43 AM
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And, most jobs the tools cost less than the mechanic's wages and markup. And you still have the tools.
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Old 03-16-2019, 01:27 PM
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Originally Posted by REELAV8R View Post
In order of cheapest to more expensive but still cheap.

new gapped plug in heat range 5 for ngk

recurve the ignition

hook up vacuum advance to manifold vacuum. Use lars’ papers to get this right.

remove air pump

remove all emissions eqipment including disabling heat riser in right side manifold.

get cliff ruggles’ book off amazon on the quadrajet and read it at least three times then rebuild your carb using one of his rebuild kits. Or pay Lars to do it for you.

replace the 2 to 1 to 2 exhaust with true dual exhaust eliminating the antique caylitic converter.

owning a car like this it is pretty much a MUST to learn how to work on it unless you have deep pockets and then you’ll just be paying a lot to have some else screw stuff up.

oh and you can replace the stock clutch fan with a good electric fan set up if you want to free up a bit of hp to the wheels.
All of this stuff....PLUS:
A high rise aluminum intake (Weiand Street Warrior, Edelbrock RPM)
Headers (Stay with Hooker or Hedman)
A real set of rocker arms (Even Comp Roller tip is light years ahead of stock)
Re-Jet Carb

At this point ir would be a solid 350hp engine on the dyno.....which is on par with L-79,L-46......and fun to drive. The L-82 cam is a great street cam and at this level the heads become the cork.

I myself would love a red 79' 4 speed modified with the above components.......I think it would be just right.

Jebby
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Old 03-16-2019, 02:28 PM
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Lot's of good ideas for speed on the cheap. The OP would have to come back to benefit from it, though.
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Old 03-16-2019, 03:53 PM
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Originally Posted by Bikespace View Post
Lot's of good ideas for speed on the cheap. The OP would have to come back to benefit from it, though.
hmmm ...OP's age 21, in college and just got a red vette ... let's hope he's busy being quite sociable... in person.
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Old 03-16-2019, 04:14 PM
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That is where reclining seats are a big help.
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Old 03-16-2019, 06:36 PM
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Originally Posted by platinummaker View Post
Quickest and easiest, most fun, and best bang for the buck......wait for it..... nitrous. Keep it at 100 hp or below and your biggest problem will be wearing out rear tires and running out of laughing gas. JMHO
Oh, and maybe speeding tickets.
great suggestion......hmmm....I have a plate kit....hmmm...
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