# Which distributor for my Le Mans ???



## kobold (Jan 5, 2019)

Hello guys,
I want to replace my distributor (with points) for a .
Engine: 400cui (1970), Heads: 62 from 1968, Tripower carbs, hot cam (doesn't know which one...)
I read, that for a HEI distributor there's not enough space.
What's about the Pertronix D7120700 ?
What is the difference to the Pertronix D7120710 ?
Any other ideas ?
Don't want to buy the wrong part(s).
Regards: Peter


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## gmjunkie (Jan 1, 2019)

You can use an HEI distributor but just have to buy one with the small cap and separate ignition coil. The common ones you see everywhere are the "large cap" with the built in ignition coil, thats what makes the cap so large. In terms of the differences in part number it looks like one has a female cap and one has a male cap. Just two different styles of spark plug wire, other than that they are identical.

I am actually looking at having an original style distributor rebuilt and converted to HEI. I'll let you know how that goes if thats the route you're looking to go. CRT performance and Packard also make small cap hei distributors but I have no idea how they run. Maybe someone else will have some input.


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## geeteeohguy (Feb 2, 2008)

My advice would be to run a stock rebuilt or good condition GM points distributor if you are after reliability. Points are more reliable than HEI and light the plugs just as well. Have used them for over 40 years in many cars for 100's of thousands of miles without issue. I can't even begin to count how many Pertronix and HEI failures I've run across in the last year alone. The problem is, most folks under 45 years of age have no idea what points are, so they don't feel comfortable with them. I say that when playing with antique cars, you should at least learn about the antique systems that made them great.


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## cij911 (Oct 25, 2017)

geeteeohguy said:


> My advice would be to run a stock rebuilt or good condition GM points distributor if you are after reliability. Points are more reliable than HEI and light the plugs just as well. Have used them for over 40 years in many cars for 100's of thousands of miles without issue. I can't even begin to count how many Pertronix and HEI failures I've run across in the last year alone. The problem is, most folks under 45 years of age have no idea what points are, so they don't feel comfortable with them. I say that when playing with antique cars, you should at least learn about the antique systems that made them great.


I would add x2.....I personally have had two Pertronix units fail and one GM HEI fail....When they go, they go and will leave you stranded.


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## bigD (Jul 21, 2016)

geeteeohguy said:


> My advice would be to run a stock rebuilt or good condition GM points distributor if you are after reliability. Points are more reliable than HEI and light the plugs just as well. Have used them for over 40 years in many cars for 100's of thousands of miles without issue. I can't even begin to count how many Pertronix and HEI failures I've run across in the last year alone. The problem is, most folks under 45 years of age have no idea what points are, so they don't feel comfortable with them. I say that when playing with antique cars, you should at least learn about the antique systems that made them great.


I suppose that everything else, other than a big cap HEI, will fit. 

I agree that points are probably the least likely system to leave you stranded. 

As for the elec systems, MSD is probably the most popular name. They have a ready-to-run system, that includes just the dist plus a remote coil. Then there are several types of "boxes". 

The MSD dist are quite expensive. 

https://www.summitracing.com/parts/...0296lDGz1ELQf1Acl5nkuTZnLsp079cxoCT5cQAvD_BwE

This Pertronix is a little cheaper & has a rev limiter.

https://www.summitracing.com/parts/pnx-d7120700/overview/make/pontiac

This Summit is cheaper, & probably Chinese made. 

https://www.summitracing.com/parts/sum-850400-1/overview/make/pontiac

Then there are some cheap Chinese models on Ebay, for less than $60, & up. I think another name for ready-to-run is small cap HEI. 

https://www.ebay.com/itm/Pontiac-32...603175?hash=item51f370be27:g:WogAAOSw5VtaBEey


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## curtis.smith68 (May 9, 2018)

bigD said:


> I suppose that everything else, other than a big cap HEI, will fit.
> 
> As for the elec systems, MSD is probably the most popular name. They have a ready-to-run system, that includes just the dist plus a remote coil. Then there are several types of "boxes".
> 
> ...


I run an MSD Pro Billet distributor, mechanical advance, with upgraded bronze cam/oil pump gear, an MSD Digital-6 Plus ignition box and MSD Blaster SS coil. Granted there is nothing stock about that but I love the performance of that combination. The built in adjustable rev limiter is awesome and a life saver to boot. It doesn't use the fuse style rev settings but a simple adjustable dial on the side so it's easy to tweak while out and about. It has built in features for starting and NOS (should you choose to go that rout, not me though) as well as a few other goodies... The Ignition box can be easily concealed under your dash if you like or mounted on the wheel well as most do and the coil is a lot smaller than most coils... food for thought... but you are right, not cheap.


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## geeteeohguy (Feb 2, 2008)

Good point on the rev limiter....If I had had one in 1987, I would not have grenaded a 428 engine I was running at the time. Rev limiters on a stick shift Pontiac are a GOOD thing!


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## gtojoe68 (Jan 4, 2019)

I run same setup as curtis.smith68 on my 68' 400. Rev limiter a plus and the MSD system works great. I do remember points, how to adjust and how much of a PITA they are. And they burn up far too often. Besides - where do you think they are made now? Very good to know where we came from and how to work on the cars. However, for ME and wanting reliability/driveability - MSD setup is way to go.


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## Rmonte (Jun 4, 2018)

I used a Summit brand hei with a pertronix module in my Firebird & it works great.
You just have to make sure you put the # 1 plug
At 1:00 not in front where it is on a Chevy.
The hei & cap should fit no problem , but if you 
Put the #1 plug in the front the. Vacuum advance hose Will hit the head where it goes past the intake & you can’t turn it to get enough advance. The distributor isn’t that close to the firewall & the pertronix module got rid of the bad exhaust smell I was having & the spark plugs look great.


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## Dano628 (Jun 18, 2019)

An HEI will fit no problem. As Rmonte said make sure you index the distributor so that #1 is at 1:00 .


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## Dano628 (Jun 18, 2019)

geeteeohguy said:


> My advice would be to run a stock rebuilt or good condition GM points distributor if you are after reliability. Points are more reliable than HEI and light the plugs just as well. Have used them for over 40 years in many cars for 100's of thousands of miles without issue. I can't even begin to count how many Pertronix and HEI failures I've run across in the last year alone. The problem is, most folks under 45 years of age have no idea what points are, so they don't feel comfortable with them. I say that when playing with antique cars, you should at least learn about the antique systems that made them great.


I can understand if you like points better but there is no way they supply anyway near the voltage as any electronic ignition.


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## PontiacJim (Dec 29, 2012)

Dano628 said:


> I can understand if you like points better but there is no way they supply anyway near the voltage as any electronic ignition.



Hmmm, so you are saying that it is the points that supplies the voltage to the plugs and not the coil?


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## Dano628 (Jun 18, 2019)

PontiacJim said:


> Hmmm, so you are saying that it is the points that supplies the voltage to the plugs and not the coil?


http://www.pontiacpower.org/HEI.pdf


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## Dano628 (Jun 18, 2019)

PontiacJim said:


> Hmmm, so you are saying that it is the points that supplies the voltage to the plugs and not the coil?


 Sorry for your confusion due to the fact that I left the word system out of my original post . But I stand by my original statement that an electronic ignition system puts out more voltage and energy than a points system.


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## Jeff's Classics (Feb 24, 2010)

If you want to run and MSD box and billet distributor and you want vacuum advance check out the Jeg's brand billet distributor.
I've had good luck with MSD 6A systems over the years unless they got wet, and I had one pickup go back in the distributor many years ago. The newer MSD Digital 6 spark boxes seem to be even more reliable than the old 6A they replaced, and they are a little easier to install with the wiring harness on a big connector now.


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## geeteeohguy (Feb 2, 2008)

Dano628 said:


> An HEI will fit no problem. As Rmonte said make sure you index the distributor so that #1 is at 1:00 .


Not if you're running a GM HEI with the coil in the cap. Not with a tripower, like the OP has.


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## Dano628 (Jun 18, 2019)

geeteeohguy said:


> Not if you're running a GM HEI with the coil in the cap. Not with a tripower, like the OP has.


 You are absolutely correct didn’t notice that it was a tripower . For my sons 65 389 tripower we used a Mallory dual point might convert it to electronic in the future .


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## gtoearl (Dec 21, 2009)

I actually have a similar motor in my 66 GTO. I have a 389 with 1966 number 16 heads. Also have 67HO exhaust. Not sure what my horsepower is as the last build I replace the pistons with a dished piston which lowered the compression ratio. I am very happy with the way it runs. As for my distributor, I have a stock distributor with a Pentronics conversion. I know there is some controversy on the reliability of Pentronics and I am sympathetic to that opinion .... but I must say I’ve been very happy with the reliability of my conversion. I’ve had it in there for almost 10 years without issue. I hope my post is helpful. I also was concerned about the stock look of the distributor.


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## PontiacJim (Dec 29, 2012)

Dano628 said:


> Sorry for your confusion due to the fact that I left the word system out of my original post . But I stand by my original statement that an electronic ignition system puts out more voltage and energy than a points system.



Yep, we have gone through this false assumption in the past here. Read it and weep - Points versus HEI. Points wins out stock for stock - and keep in mind the stock RPM for the Pontiac is 5,200 RPM's, but can be safely run a little higher. https://www.hotrod.com/articles/ccrp-9812-ignition-performance-test/ 

Now, if you want to argue a bit more, let's consider dual points vs HEI. 

The real advantage, if any, is that an HEI or electronic ignition is used by those owners who cannot install, nor set the gap/dwell, nor recognize when the points are tapping you on the shoulder letting you know that they are going bad. The advantages of the HEI is all in their heads and articles they read on the internet. :yesnod:


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## Dano628 (Jun 18, 2019)

PontiacJim said:


> Yep, we have gone through this false assumption in the past here. Read it and weep - Points versus HEI. Points wins out stock for stock - and keep in mind the stock RPM for the Pontiac is 5,200 RPM's, but can be safely run a little higher. https://www.hotrod.com/articles/ccrp-9812-ignition-performance-test/
> 
> Now, if you want to argue a bit more, let's consider dual points vs HEI.
> 
> The real advantage, if any, is that an HEI or electronic ignition is used by those owners who cannot install, nor set the gap/dwell, nor recognize when the points are tapping you on the shoulder letting you know that they are going bad. The advantages of the HEI is all in their heads and articles they read on the internet. :yesnod:


I have read that article as well . All it proves that a well set up point system on a small block Chevy makes slightly more power at a couple different rpms . It doesn’t sound like they used a larger spark plug gap for the HEIs . It does show above 5200 rpms points making more power . But Pontiac engines generally make peak hp around 5000 rpm or less and tq.around 3500 . I’m a retired Aviation mechanic, I’ve installed and set hundreds of set of points single ,dual , and magnetos and I run electronic for the easy starts , consistent performance , and zero maintenance .


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## geeteeohguy (Feb 2, 2008)

PontiacJim said:


> Yep, we have gone through this false assumption in the past here. Read it and weep - Points versus HEI. Points wins out stock for stock - and keep in mind the stock RPM for the Pontiac is 5,200 RPM's, but can be safely run a little higher. https://www.hotrod.com/articles/ccrp-9812-ignition-performance-test/
> 
> Now, if you want to argue a bit more, let's consider dual points vs HEI.
> 
> The real advantage, if any, is that an HEI or electronic ignition is used by those owners who cannot install, nor set the gap/dwell, nor recognize when the points are tapping you on the shoulder letting you know that they are going bad. The advantages of the HEI is all in their heads and articles they read on the internet. :yesnod:


Lars Grimsrud wrote a very interesting article that backs this all up....everybody here should be familiar with him. He is known throughout the industry as THE go-to-guy in ignition systems, and is a real engineer who has forgotten more than most of us know....he did a test with a Ford 302 and found zero improvements anyplace over stock points using various high-zoot, high tech HEI systems. The guys I know who ditch points for modern tech do so from lack of understanding of the system and simple hype, IMO. As an ex-tune-up mechanic who literally tuned up thousands of cars from the late '70's through the mid '90's, from personal experience, I back up what Jim says. I can't begin to even count how many cars I had towed in with failed HEI units.....vs the handful of cars that came in on a hook with a bad condenser, or more commonly, worn out ignition points that had been run for 60,000 miles.


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## kobold (Jan 5, 2019)

Thanks a lot for all the answers.
I'm also post 50 years old, and I know how to adjust Points.
My (the car's) problem is, that at low rpm the idle is is not smooth, I was told (from more than one specialist here in germany) because of the hot cam. (because the car came from the states, I have no further Information, which cam is inside.) So, at higher rpm, the engine runs well and there's no leakage at the engine, I don't want to "examine" and/or rebuild the engine.
So, I'd like to try to convert to a Pertronix ignition System (incl. coil), and hope, it helps.
so Long, Peter


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## geeteeohguy (Feb 2, 2008)

The means of triggering the spark will have no bearing on curing a rough idle caused by a hot cam due to low engine vacuum. Either the spark lights the plug or it doesn't....it doesn't know if it's being triggered by points or hei.....as long as all the plugs are firing, it'll run the same with either distributor. Just less reliably with the Pertronix unit over time. The only cure for a lopey idle caused by a hot cam is to install Rhodes lifters or replace the cam with something close to stock.


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## kobold (Jan 5, 2019)

One more question:
With ignition on (no crancking), I measure 8 to 9 Volts at the coil.
When crancking, I measure 10 to 11Volts at the coil.
In the wireing plan, I cannot see any resistor or something else.
So, is it possible to run a Pertronix ignition (with external coil) without a Relais for having direct Batterie voltage at the coil ?
From where can I get the ignition 12 Volts (when not using a Relais)?
Does anyone here in the forum use a Pertonix without a Relais on a 1968 LeMans (GTO) ?
Regards: Peter


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## Red Skeleton (Jul 2, 2019)

geeteeohguy said:


> Lars Grimsrud wrote a very interesting article that backs this all up....everybody here should be familiar with him. He is known throughout the industry as THE go-to-guy in ignition systems, and is a real engineer who has forgotten more than most of us know....he did a test with a Ford 302 and found zero improvements anyplace over stock points using various high-zoot, high tech HEI systems. The guys I know who ditch points for modern tech do so from lack of understanding of the system and simple hype, IMO. As an ex-tune-up mechanic who literally tuned up thousands of cars from the late '70's through the mid '90's, from personal experience, I back up what Jim says. I can't begin to even count how many cars I had towed in with failed HEI units.....vs the handful of cars that came in on a hook with a bad condenser, or more commonly, worn out ignition points that had been run for 60,000 miles.


Lars also says to use a vacuum advance for street ability at lower speeds to keep your car from chugging. Stay away from mechanical advance only unless you're racing.:wink3:


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