Hei distributor recommendation - Pontiac GTO Forum
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post #1 of 19 (permalink) Old 06-02-2018, 12:01 PM Thread Starter
 
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Hei distributor recommendation

Hello- I was hoping someone could give me a recommendation on an hei distributor. I have a 421 tri power, stock cam, and currently have a points distributor. The clearance with the intake manifold and the distributor cap is tight already, I doubt one of those large hei caps is going to work. What after market is best?

And also wondering if I were to pull one out of a junkyard, what would be the right car to pull from?

Thanks for your thoughts...
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post #2 of 19 (permalink) Old 06-02-2018, 02:23 PM
 
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Welcome to the forum. Desiring to go the HEI route with a tripower intake, your best bet is to have board member Dave Ray build you a small body HEI. Have several longtime Pontiac friends with early cars who have gone with a small body HEI from Dave.
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post #3 of 19 (permalink) Old 06-02-2018, 09:33 PM Thread Starter
 
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Ok thanks, I’ll drop him a pm
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post #4 of 19 (permalink) Old 06-03-2018, 06:25 AM
 
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Not trying to hijack your thread, but if you already have a points distributor, why would you go to an HEI? I see this change quite often and wonder why?? What is so wrong with a points distributor?? It worked well at one time. Can it have something to do with changing the points every so many thousand miles?? That's not a big deal. Besides, how many miles do we put on these cars during a season?? I read more threads with problem HEI distributors then I do the point ones. I admittedly have an HEI distributor in my '71 GTO, because it came with it. I also bought a used point distributor. The first sign of trouble with the HEI, in the garbage it goes. I know I'll need a coil and resistor, rewire some, but that's ok. By asking these questions, I'm just trying to learn something. Many thanks.
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post #5 of 19 (permalink) Old 06-03-2018, 07:35 AM
 
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Not trying to hijack your thread, but if you already have a points distributor, why would you go to an HEI? I see this change quite often and wonder why?? What is so wrong with a points distributor?? It worked well at one time. Can it have something to do with changing the points every so many thousand miles?? That's not a big deal. Besides, how many miles do we put on these cars during a season?? I read more threads with problem HEI distributors then I do the point ones. I admittedly have an HEI distributor in my '71 GTO, because it came with it. I also bought a used point distributor. The first sign of trouble with the HEI, in the garbage it goes. I know I'll need a coil and resistor, rewire some, but that's ok. By asking these questions, I'm just trying to learn something. Many thanks.
From what I gather, the HEI was developed to meet Federal requirements that the emission systems to be warranted for 50,000 miles. Points won't last that long without maintenance, but an HEI usually will. The cars of that era also ran leaner mixtures which demanded greater voltage and more spark energy to kick off combustion. So the HEI is seen by some as a lower maintenance item.

Points will always give you a "heads up" when they are going bad by running rough. When the module in an HEI quits, no warning and it can leave you stranded.

The HEI when first out was not really designed for high RPM and was not very good over 5,000 RPM's. The advance curves were also The advance curve on a stock HEI is for the most part not fully advanced until 4,000-4,500 rpm, which is very slow. If your low-end cam power band begins at 2,500 rpm (or below), then your advance curve will not be matched to your camshafts power-band, which will result in a significant horsepower/torque loss.

The HEI provided a longer spark dwell and hotter spark so low to midrange motors benefit from a more intense spark from idle, all the way up the entire rpm range as the fuel is burned more completely. Since the HEI produces more voltage and amperage output than a point-type ignition, it required a larger-diameter cap to prevent voltage crossfire inside the distributor cap. The large cap also offers extra space to host the coil, making the HEI distributor self-contained. It also allowed for a wider spark plug gap for a more complete burning of the fuel mixture.

Is the HEI really any better than points? I guess that depends. Most today have no clue on how to set up points and have been convinced that electronic ignitions are the only way to go. You need a tach/dwell meter to really set them up correctly - and that's an extra "tool" that many either don't want to invest in or care to understand its use. Want more dwell, use a dual point distributor or and MSD box. Hotter spark? Upgrade to a hotter coil. Need stability at higher RPM's, get a set of points designed for more RPM's having additional tension on the points.

For me, electronic ignition is a convenience and in my mind, dependable over a longer period of time. It will outlast points in the long run, but will/can leave you stranded if the module quits on you. You can either keep a spare set of points in your glove box or a module.

As far as more power from the engine, take a look at this comparison done by Hot Rod. Points seems to be the winner up to about 6,500 RPM's - which is probably when points begin to bounce unless you have the heavy duty set. What the test does not show, as this is a stock distributor, is how the distributor might actually outperform the electronics if they first threw in the results of a dual point distributor designed for higher RPM's and then adding an MSD or other unit that enhances spark.

So the bottom line appears to be, no real advantage in the functionality of an HEI over a points distributor unless you begin to go higher in RPM's - which I think could be matched by setting up the distributor to handle the higher RPM's just as they did in drag racing past. The only advantage to HEI is not one of functionality, but longevity and reliability from the module over a greater period of time/miles versus points.

Ignition Performance Test - Hot Rod Network
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post #6 of 19 (permalink) Old 06-03-2018, 08:48 AM
 
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Originally Posted by MidnightAuto View Post
Hello- I was hoping someone could give me a recommendation on an hei distributor. I have a 421 tri power, stock cam, and currently have a points distributor. The clearance with the intake manifold and the distributor cap is tight already, I doubt one of those large hei caps is going to work. What after market is best?

And also wondering if I were to pull one out of a junkyard, what would be the right car to pull from?

Thanks for your thoughts...
I also run a tripower, I pulled the original points distributor and put it in safe storage. I bought the pertronix billet distributor with the flame thrower 3 module and flame thrower coil. It is the same size as a points distributor, uses the same plug wires and looks like the original to most, but you get the added benefit of msd and a adjustable rev limiter. It is super simple to change out and adjust, plus I was able to keep my points distributor intact in case I want to switch it back. I believe it cost less than 300$ for the distributor and coil. The only thing that you have to do is get rid of the resistor wire so you run 12 volts to the distributor. The plug wires I had were compatible but the directions say that certain kinds are not.

Check it out on line and you can read the directions and before purchasing.

Good luck and keep us posted.
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post #7 of 19 (permalink) Old 06-03-2018, 02:24 PM Thread Starter
 
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ok got it, thanks for the extra words. nicholas to answer your question from my pov, it was history for me. I had a points distributor in my last engine and it was a pain. more than once i was on the side of the road and had to literally sand down the points with the back of a pack of matches to get the car running again. After I switched to an HEI pulled from a junkyard, I never had a problem again. granted that was 30 years ago, but i still remember, and hence my thought to just avoid that from the start. pontiacjim has put some real info out there, not just my focus group on one, so that is very helpful to know. I'll check out the petronix and I did connect with Dave and will talk with him next week. I see now that it looks like he takes your existing distributor and changes, so understand 65goat point on having the original un-modified in the closet. again, thanks all. will keep you posted.
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post #8 of 19 (permalink) Old 06-03-2018, 03:34 PM
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.... if you already have a points distributor, why would you go to an HEI? I see this change quite often and wonder why?? What is so wrong with a points distributor??
To be brutally honest... on a street car or even a street/strip car that rarely if ever runs over 6000-6500 rpm, there's no compelling reason to abandon the points system. At high rpm, the problem with a points system (and even some electronics) is that they start to have trouble firing the plugs because there's just not enough time to build up a full 'charge' in the coil. Addressing that problem back in the day was the reason for dual points distributors, and then later electronic 'capacitive discharge' systems. Systems that work by 'charging up' a single coil and then discharging it are going to have problems at high rpm, regardless if the mechanism is mechanical (points) or electronic. As has already been said, when a points system starts to go south on you, there's some warning. An electronic system is an all or nothing proposition and usually fails with no warning. There have been side by side tests to see if electronic systems somehow work better or make more power than points systems do over the rpm ranges where most of our cars live, and they don't.

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post #9 of 19 (permalink) Old 06-04-2018, 06:40 AM
 
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Bear and Pontiac Jim, thanks for taking the time to share. You both put a lot of effort into this. I now have a better understanding and more knowledge about the HEI. In my '71 GTO, I'm going to leave things as they are for now. The motor starts and runs great. Seldom see's 5000 rpm's. I am going to look into getting a spare module for the glove box, just in case. Never knew about that.
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post #10 of 19 (permalink) Old 06-05-2018, 06:10 AM
 
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Is the HEI really any better than points? I guess that depends. Most today have no clue on how to set up points and have been convinced that electronic ignitions are the only way to go. You need a tach/dwell meter to really set them up correctly - and that's an extra "tool" that many either don't want to invest in or care to understand its use. Want more dwell, use a dual point distributor or and MSD box. Hotter spark? Upgrade to a hotter coil. Need stability at higher RPM's, get a set of points designed for more RPM's having additional tension on the points.

I remember going through all that. No internet, Hunting down a good set of heavy duty points, every other parts store sold the “Uni-set” - points and a condenser in one. So many cheap variations. Then I got a dual point distributor, with heavy duty points from Accell, an MSD 6AL , with the plug in “pills or modules” for a rev limiter and a “Blaster coil” – went through the process to setup the points, checked the dwell, every few thousand miles. Car was a 68 that was my daily driver. Even mounted the MSD box in the car… Worked very well. When I swapped the engine I used a junk yard HEI from a 75 Grand Am to get it running.

No fuss, no extra parts. The cap and rotor were well used and the wires were old. I was amazed how well it ran and after break in buzzed right past 6000 rpm.
Never turned back…..
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