Wiring needed for 3.0 with stock dizzy- using carbs

[914obsession]

I'm doing a 914-6 conversion, I'll be installing a 78 3.0 with it's stock distributor (magnetic pick-ups) using a set of carbs. I was going to get an early 911 (with CDI) engine wiring harness to use to mate this with my relay board. I have a 3 pin CDI box that I was going to use. From what I'm being told, the 78 distributor needs the 6 pin CDI box. Can anyone tell me what the best route is for my wiring, do I need to buy a CIS engine harness along with the 6 pin CDI harness to mate with my relay board?

Thanks,

Dan

[Henry Schmidt]

MSD 6AL ignition box is your easiest fix. Come with wiring and diagram to make installation easy.
Inexpensive and modern.

[Eagledriver]

As Henry says, aftermarket CDI is the easiest (and cheapest) solution. I use the Mallory Hi-Fire 6AL. MSD has the best reputation (although I've seen them fail also). On my SC engine I found that the green wire in the purple/green pair goes to the green wire on the distributor. If you get it backward the ignition will be about 30 degrees more advanced (hence the warning about engine damage). You can detect this right away with a timing light before driving the car so it's easy to fix.

-Andy

[tom1394racing]

Dan

If you are keeping the CIS, the 78/79 harness is the best route independent of whether you use the MSD or 6 pin CDI.

[Henry Schmidt]

Old harnesses are generally crappie. Hard and crispy.
We make custom harnesses for this exact application.
I would avoid using the old harness unless there is no other choice.
The CIS harness has more wiring than a carburated engine needs so why make life harder than it already is?

[914obsession]

Henry, I no longer have the "green wire" plug that connects to my distributor, I made up a different connector that works really well, the only problem is that I do not know which of the two wires to hook up to the two MDS 6AL wires? It's a stock 3.0 distributor, if you remove the cap and dust shield there are two markings near the two connector prongs that leave the distributor "A" and "B", how do I hook these up?

Dan

[Eagledriver]

I'm not at home so I can't look inside my dizzy but maybe someone on here can. If not just hook it up either way and start the car. Don't drive it just start it. If the timing is close to TDC then you have it hooked up correctly. If you have it hooked up backward the idle will be fast and the ignition will be advanced about 30 degrees.

Static time the dizzy by setting the magnet fingers abeam the stationary fingers while the engine is at TDC. If you hook up the wires correctly the MSD will fire when the fingers pass each other. If you hook it up backward the MSD will fire as the rotating fingers approach the static fingers.

-Andy

[Henry Schmidt]

Originally Posted by 914obsession

Henry, I no longer have the "green wire" plug that connects to my distributor, I made up a different connector that works really well, the only problem is that I do not know which of the two wires to hook up to the two MDS 6AL wires? It's a stock 3.0 distributor, if you remove the cap and dust shield there are two markings near the two connector prongs that leave the distributor "A" and "B", how do I hook these up?

Dan

Dan, the answer to your question is in the illustration I posted earlier.

[Carrerax]

Originally Posted by Henry Schmidt

Old harnesses are generally crappie. Hard and crispy.
We make custom harnesses for this exact application.
I would avoid using the old harness unless there is no other choice.
The CIS harness has more wiring than a carburated engine needs so why make life harder than it already is?

Henry, Im going to be installing a 78 3.0 with stock SC dizzy in a 1970t with PMO carbs. I really like the idea of a new engine harness. I have the original T one and the Sc one if you need a donor for parts. Please PM me a price for a harness that will plug and play into my 70t chassis with a MSD.