# wanting to change a 72 400 to electronic ignition



## LastOutlaw (Jun 30, 2009)

My son has a 1972 Pontiac Ventura with a 400 in it and has been having problems with the distributor points settings changing. He says the point gap is changing after a day or so of driving. He is in another state so I can't really look at it with him. According to him the plate that the points bolts down on seems to wiggle a good bit. My GTO was changed over a number of years ago to electronic ignition and if I remember correctly we threw a Chevy Distributor in it and it was real easy to do. My question is if he goes this route, what wires does he need to run to the new electronic dist and where from? Mine has a plug with 3 wires plugged into the back socket of the dist. and one wire plugged into the front socket of the electronic dist.
The 3 wire plug looks like white or tan, black and brown? Hard to tell as my engine compartment is pretty dirty now with bodywork going on. The single wire is red. Any info will be relayed to him.
Thanks.


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## LastOutlaw (Jun 30, 2009)

*bump*

bumpity bump


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## tyscru (Sep 29, 2009)

I went to a performance shop and bought a conversion kit that bolted into where the points bolted in. The kit came with wiring diagrams and was easy to install. It's great not having to set points any longer. They also have an aftermarket performance electronic distributor that will replace the existing distributor. I wish I had spent the extra money to get the performance distributor for my GTO.
I understand that the GM HEI distributors will work as well but because the coil is mounted on the top the distributor head is bigger and may present clearance problems.


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## Edelbroke (Jan 31, 2010)

Bump..
So does an HEI distributor for a BOP or even a chevy fit in a Pontiac 400?


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## Rukee (Feb 8, 2007)

Pontiac is Pontiac only on the distributor. You can drop in a Pontiac HEI. The three wires on the inside plug come from the ignition module in the base of the distributor. Only need to supply keyed 12v + to the battery connection on the outside plugs. Run his tach wire to the other outside plug.
The plate the points are on should wiggle, it moves with the vacuum advance, not saying it's not worn out in his, but it does move somewhat.
I opted for an MSD unit, which provides multiple spark per revolution, hotter spark, rev limiter with the stock points. The original points have the coil ground through the points and that sparking action is what wears the points. The MSD unit only monitors resistance through the points like a multimeter so there is no wear and they last forever. Have had the same set in mine for years without an adjustment.


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## jetstang (Nov 5, 2008)

You can buy a brand new Pontiac HEI on the auction site for $70?, thats what I do, all new parts and billet case. 1 power wire and hook up the tach wire and that's it.


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## the65gto (Oct 9, 2008)

Rukee said:


> Pontiac is Pontiac only on the distributor. You can drop in a Pontiac HEI. The three wires on the inside plug come from the ignition module in the base of the distributor. Only need to supply keyed 12v + to the battery connection on the outside plugs. Run his tach wire to the other outside plug.
> The plate the points are on should wiggle, it moves with the vacuum advance, not saying it's not worn out in his, but it does move somewhat.
> I opted for an MSD unit, which provides multiple spark per revolution, hotter spark, rev limiter with the stock points. The original points have the coil ground through the points and that sparking action is what wears the points. The MSD unit only monitors resistance through the points like a multimeter so there is no wear and they last forever. Have had the same set in mine for years without an adjustment.


I was just over to the online auction site and see a complete unit "Pontiac HEI 50K v coil etc" with the number 6504-R @ $45.00. As far as the 12v switched line...does this use the factory oem resistance wire or do you bypass this when in the "RUN" position on your ignition switch. Besides possible clearance issues, I believe this will fit my 65 389? (I still have points)


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## Rukee (Feb 8, 2007)

If you have the tri-power set up in your avatar, the HEI will not fit. It hits the back of the intake manafold.


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## the65gto (Oct 9, 2008)

Rukee said:


> If you have the tri-power set up in your avatar, the HEI will not fit. It hits the back of the intake manafold.


Thanks for saving me a big OOPS! I read that the HEI is 1.5" bigger in diameter and 1.0" taller. Was going to try and mock it up this afternoon but never got around to it...


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## 60sPontiacs (Jul 14, 2016)

Looking now to do this to a 9.5:1 72 400 engine (not stock). HEI from a 75 GP fits a 72 400 - and will probably be okay if your compression is similar (8:1), but the distributor specs (vacuum and centrifugal advance) are completely different for older higher CR engines. With 1975 HEI in the 69 428 10.25:1 engine, the car had no power off line when set to 6BTC (stock as it was with points distributor), and if I advanced timing to run well off the line, it'd detonate when cruising. Could be the 69 distributor is set up for manifold vacuum and the new for ported, as well as different full vacuum and full mechanical advance (along with how the springs control the mech advance curve). HiPerf distributors (like an accel on a 67 10:1 grand prix, can be adjusted. Everything changes as engine is modified from stock (CR, cam, etc) which is shown by Pontiac making a gazillion types of factory distributors - they look the same but had difference characteristics. Like setting up a carb for best performance, distributor "curving" is precise and makes a world of difference - especially with today gas.

Easiest fix it to get a Pertronix bolt on to replace the points/condenser/rotor - then advance/curve specs remain the same.


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