Im in the process of doing the HEI conversion ( a little at the time ).
My question is , Do I not hook up the negative coil wire from the old coil to the new one?
I looked at the wiring diagrams and it looks like the negative wire just goes to the hookup for the lean burn computer, and the positive goes to the ecu, but also to other components.I thought I read here somewhere to leave that negative wire off , but I can't find it now.

Thanks
Dave

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81 Dodge D150
It looked easier in the book .

bump

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81 Dodge D150
It looked easier in the book .

Negative coil wire goes to the HEI module and positive goes to a switched 12 volt source.

If you're converting from a Lean Burn you need a distributor with vacuum and mechanical advance - unless you're like me and running a 7 pin HEI module with the timing controlled by an aftermarket ECU.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Thanks for the reply Matt
Forgive me if I am reading this wrong , but I run the negative wire from the old coil to the HEI module and run the pos. and neg. wires from the module to the new MSD coil. Can I run the pos. wire from the old coil to the new coil. I dont want to sound ignorant , but I dont want to screw this up . All of the posts I found on the HEI conversion were for pre-lean burn vehicles dealing with the ballast resistor. I did finally find a post last night of a lean burn vehicle and that person was told that only the negative wire from the module goes to the coil unless for a tach.
So if I have to run that old negative wire to the module that is good to know.
Maybe someone can update the Hei conversion article for lean burn vehicles.
Thanks
Dave

_________________
81 Dodge D150
It looked easier in the book .

There's two sorts of HEI conversions for Lean Burn vehicles.

One is to replace the Lean Burn distributor with the old style distributor. In this case, you'd run 12 volts to the positive terminal of the coil (I believe the stock 12 volt feed wire does this as Lean Burns have no ballast resistor), and the negative terminal of the coil is only wired to the HEI module and the tach - nothing else. You're pretty much combining the Lean Burn-ectomy with the HEI mod in one step.

The other method is what I'm running on my Dart. It keeps the Lean Burn distributor but uses a separate aftermarket box to control the timing. If you're looking for a simple and easy ignition retrofit, this method's not what you are looking for.

_________________
"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Ok that is what I thought , thanks for replying back

Dave

_________________
81 Dodge D150
It looked easier in the book .