81 Distributor question
Thread Starter
Racer
Joined: Mar 2006
Posts: 343
Likes: 0
From: Davenport Ia
81 Distributor question
After many had tried to talk me out of it I had finally had enough with stock computer carb. It had alot to do with on going minor issues and alot more to do with finding a brand new Holley on Ebay cheap. Anyway I am changing the carb to a non-comp style and disabling the computer.
Isn't the 81 HEI the same as the earier HEI just with full mechanical advance instead of vacuum and mechanical?
Can it be changed over to the older specs by adding vacuum advance or module or ect?
Will the stock 81 distributor still work or will I need to change it over to a regular HEI? (76-80 vintage)
Will any of the new style HEI's work? (the small cap or flat top versions)
Will the distibutor wiring be ok or will it need changed?
Isn't the 81 HEI the same as the earier HEI just with full mechanical advance instead of vacuum and mechanical?
Can it be changed over to the older specs by adding vacuum advance or module or ect?
Will the stock 81 distributor still work or will I need to change it over to a regular HEI? (76-80 vintage)
Will any of the new style HEI's work? (the small cap or flat top versions)
Will the distibutor wiring be ok or will it need changed?
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
my .02
Regular HEIs need Power, ground and a tach signal, so yes you will have to make a couple changes
After many had tried to talk me out of it I had finally had enough with stock computer carb. It had alot to do with on going minor issues and alot more to do with finding a brand new Holley on Ebay cheap. Anyway I am changing the carb to a non-comp style and disabling the computer.
Isn't the 81 HEI the same as the earier HEI just with full mechanical advance instead of vacuum and mechanical? Nope, no mechanical or vac advance, its all electronic
Can it be changed over to the older specs by adding vacuum advance or module or ect? Not worth the effort, get a regular GM HEI
Will the stock 81 distributor still work or will I need to change it over to a regular HEI? (76-80 vintage) It will function, I don't know what the advance curv will do since the o2 sensor will be freaking out and there will be no TPS signal to the ECM
Will any of the new style HEI's work? (the small cap or flat top versions) Probably
Will the distibutor wiring be ok or will it need changed?
Isn't the 81 HEI the same as the earier HEI just with full mechanical advance instead of vacuum and mechanical? Nope, no mechanical or vac advance, its all electronic
Can it be changed over to the older specs by adding vacuum advance or module or ect? Not worth the effort, get a regular GM HEI
Will the stock 81 distributor still work or will I need to change it over to a regular HEI? (76-80 vintage) It will function, I don't know what the advance curv will do since the o2 sensor will be freaking out and there will be no TPS signal to the ECM
Will any of the new style HEI's work? (the small cap or flat top versions) Probably
Will the distibutor wiring be ok or will it need changed?
Pro
Joined: Nov 2007
Posts: 741
Likes: 1
From: Woodstock GA
There should only be two wires going to the HEI, a red or pink wire for power + and a black - for the tach. I did a similar conversion on an 87 Trans Am a few years ago, and it was very straightforward. I don't believe any computer -controlled style distributor is going to run right, as there is nothing to change the advance. I traded my old CC stuff (carb, distributor, computer) to a guy who was restoring a car back to stock, so the cost was $0 for me.
Thread Starter
Racer
Joined: Mar 2006
Posts: 343
Likes: 0
From: Davenport Ia
I just got an Accel hei for $20
Ok ...... Can I just change the distributors and the wiring is the same or not?
Should I unplug the computer or just leave it hooked up?
To me it seems I should just tape off the carb wires ,remove the check engine bulb and plug in the new distibutor. I just dont for sure.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Good question. I know the TCC lockup is controlled by Engine Temp, Vehicle Speed, Tach input...
Don't know if any other sensors or inputs are required. If thats the case, all you have is the TCC controlled by the ECM, so at that point I would go with the BTO Lockup kit.
Some of the other guys might pop in on this, Mine is not running yet so I can't check it that far
Don't know if any other sensors or inputs are required. If thats the case, all you have is the TCC controlled by the ECM, so at that point I would go with the BTO Lockup kit.
Some of the other guys might pop in on this, Mine is not running yet so I can't check it that far
Thread Starter
Racer
Joined: Mar 2006
Posts: 343
Likes: 0
From: Davenport Ia
I am planning on changing the trans to an overdrive type. I am not planning this anytime soon though. Will the trans slip or just not lock up at high speed? Will it really hurt anything other then mpg on the highway?
The part that sucks is the 2 things I understand the least are the computer and the trans.
Now I am dealing with both at the same time.
The part that sucks is the 2 things I understand the least are the computer and the trans.
Now I am dealing with both at the same time.
Burning Brakes
Joined: Dec 2007
Posts: 952
Likes: 0
I am planning on changing the trans to an overdrive type. I am not planning this anytime soon though. Will the trans slip or just not lock up at high speed? Will it really hurt anything other then mpg on the highway?
The part that sucks is the 2 things I understand the least are the computer and the trans.
Now I am dealing with both at the same time.
The part that sucks is the 2 things I understand the least are the computer and the trans.
Now I am dealing with both at the same time.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
you have a lockup system already, the 4 speed auto your talking about is a 2004R or 7004R. Both have electrically operated TCC valve. You car is already wired for it. I would give a try and see how it goes as is. If it does not lockup without the carb and dizzy, you will nwwd to do a lockup circuit like BTO has. Basically it supplys 12v to the tranny thru a brake pedal sw, in the trans there is a pressure switch that only closes if the tranny is happy in 3rd or 4th.