C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

1981 Replacing Carb, Need Help

Thread Tools
 
Search this Thread
 
Old Apr 5, 2015 | 12:39 PM
  #1  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default 1981 Replacing Carb, Need Help

I have bought an Edelbrock Performer EPS non-EGR intake and will be buying a carb and distributor to go to a traditional non-computer controlled setup. I know I need the 1980 and earlier style distributor, but the rest I'm not sure of.

While I'm already replacing the distributor, should I go with something performance or just a stock style?

What characteristics do I need to look for when choosing a carb? Vacuum/mechanical? Electric choke? Etc...

I know not everyone agrees with going away from the computer setup, but please keep comments directed to help me move forward with this swap.

Thank you,
Zak.
Reply
Old Apr 5, 2015 | 12:52 PM
  #2  
lars's Avatar
lars
Tech Contributor
Supporting Lifetime Gold
25 Year Member
Conversation Starter
Photogenic
Top Answer: 3
 
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
Default

For carb, run the carb you're comfortable with setting up and tuning. The Q-Jet and the Holley-type carbs, within the same cfm range (750), will perform the same, with the Q-Jet having a slight advantage in torque at low rpm. With the Q-Jet, you can make the car appear stock. The Holley and Holley-type carbs have more "wow" factor if properly installed. You can run any Chevy passenger car Q-Jet from 1976 - 1979, install an electric choke on it, and make it look "correct" without any significant mods to linkages, fuel lines, and air cleaner. With the Holley carbs, you can buy a new carb, and parts will be available. On the Q-Jets, you'll have to find a good used core carb and rebuild it. So run what suits your purpose. The Edelbrock carbs are re-pops of the old Carter AFB, and several of us have shown on the dyno that these carbs will not perform with the Q-Jet and Holley carbs. But they run reasonably well "out-of-the-box" if your only goal is to get the engine running.

On the distributor, you have nothing to gain by going with a "performance" distributor over a stock setup. The power and performance is all in the setup and curve, so run a distributor that is easily tunable for curve length and curve quickness. Set it up per my timing papers. Be sure to run one with vacuum advance.

Good luck with the tuning and setup. Feel free to contact me if you need specific info.

Lars
V8FastCars@msn.com
Reply
Old Apr 5, 2015 | 12:58 PM
  #3  
74modified's Avatar
74modified
Burning Brakes
 
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
Default

I like late model computer control, but would rather have old school non computer than the 80's stuff. Just guessing on a number of things, but sounds like a "stock" style HEI and vacuum secondary would work for you. The HEI is more than adequate for normal street RPM and cylinder pressures. If everything else is stock, you will be fine. I do like double pumper carbs, because I always go with a manual trans, but you probably have an auto.
Reply
Old Apr 5, 2015 | 01:03 PM
  #4  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

Thanks guys. So with the carb I need vacuum secondaries and electric choke...anything else I need to make sure it has to bolt up and work with all my current stock components?

I like the Barry Grant (Holley essentially) and have been thinking about going with the Speed Demon. Would this be a good selection?

Thank you for your help.
Reply
Old Apr 5, 2015 | 01:11 PM
  #5  
lars's Avatar
lars
Tech Contributor
Supporting Lifetime Gold
25 Year Member
Conversation Starter
Photogenic
Top Answer: 3
 
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
Default

I like the BG Speed Demon carbs, and I use a lot of them. It's not a direct replacement for your Q-Jet, so there will be some fabrication involved with linkages and fuel lines. I prefer them without the choke. The BG carbs need a little setup and tuning, but you can drop me an e-mail for my BG Setup and Installation paper, which has step-by-step photos for installing the BG on your engine, along with the setup required.

Lars
Reply
Old Apr 5, 2015 | 01:14 PM
  #6  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

Thank you Lars. This may be a stupid question, but they list a vacuum secondary and an annular vacuum secondary. What is the difference and which would be better to go with? And go without electric choke?
Reply
Old Apr 5, 2015 | 01:23 PM
  #7  
lars's Avatar
lars
Tech Contributor
Supporting Lifetime Gold
25 Year Member
Conversation Starter
Photogenic
Top Answer: 3
 
Joined: Aug 1999
Posts: 14,373
Likes: 6,371
From: At my Bar drinking and wrenching in Lafayette Colorado
Default

Some of these decisions simply become personal preference. I have found that the BG carbs, when correctly set up, don't need a choke. In fact, the choke seems to run the carb over-rich when cold. Without a choke, the engine is a little "balky" for the first 2 minutes of operation, which doesn't bother me. If you want the engine to start and run cold like a fuel injected engine, you might want to retain the choke and fiddle with it until you get the setup just right.

The annular boosters provide stronger metering signal at low rpm, and the fuel is discharged evenly around the inner booster ring. I've run both annular carbs and downleg carbs, and I've never been able to detect a difference between the two.

Lars
Reply
Old Apr 5, 2015 | 01:27 PM
  #8  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

Thank you, this is exactly what I needed to know. I will be ordering a distributor and carb soon.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Apr 5, 2015 | 02:01 PM
  #9  
commander_47's Avatar
commander_47
Burning Brakes
10 Year Member
Conversation Starter
Liked
Community Favorite
 
Joined: Oct 2011
Posts: 956
Likes: 86
From: McDonough Georgia
Default

Originally Posted by zakbradshaw
I have bought an Edelbrock Performer EPS non-EGR intake and will be buying a carb and distributor to go to a traditional non-computer controlled setup. I know I need the 1980 and earlier style distributor, but the rest I'm not sure of.

While I'm already replacing the distributor, should I go with something performance or just a stock style?

What characteristics do I need to look for when choosing a carb? Vacuum/mechanical? Electric choke? Etc...

I know not everyone agrees with going away from the computer setup, but please keep comments directed to help me move forward with this swap.

Thank you,
Zak.
Lars is recommending a 750 cfm, but in fact your car will probably not go that high.

Don't get me wrong here, 750 Holley is great, but could be overkill.

The vast majority of cars don't need more than 650 or so, and thats if flat out racing.

Check out the CFM calculator at Summit to get a better idea. Most cars will never get above 6000 rpm.
http://www.summitracing.com/expertad...cfm-calculator


For a stock or mildly modified car, a standard HEI distro will work fine. Summit has a real good one at a fair price:

I have used three of these with no issues whatsover:

http://www.summitracing.com/parts/sum-850001r/overview/
Reply
Old Apr 5, 2015 | 02:07 PM
  #10  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

I was planning on going 750 anyway. My 78 Camaro had a 350 with a 750 Edelbrock and it ran great with the 750.
Reply
Old Apr 5, 2015 | 04:52 PM
  #11  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

Commander, that distributor should bolt straight up and work with all my existing components right?
Reply
Old Apr 5, 2015 | 06:22 PM
  #12  
commander_47's Avatar
commander_47
Burning Brakes
10 Year Member
Conversation Starter
Liked
Community Favorite
 
Joined: Oct 2011
Posts: 956
Likes: 86
From: McDonough Georgia
Default

Yes, it will drop right in.

Plug in your tach filter.

Dont forget to put #1 at tdc.
Reply
Old Apr 5, 2015 | 06:36 PM
  #13  
zakbradshaw's Avatar
zakbradshaw
Thread Starter
Instructor
 
Joined: Mar 2010
Posts: 129
Likes: 1
From: Fort Worth Texas
Default

Great, thank you.
Reply

Get notified of new replies

To 1981 Replacing Carb, Need Help





All times are GMT -4. The time now is 06:51 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE