[79 Phoenix]

I am working on a 71 GT-37. It has a 76 400 engine and HEI distributor. I bought a new engine wiring harness and a HEI power feed wire from Ames. The harnesses are made by M&S. I didn't get any written instructions from Ames so they referred me to M&S. M&S didn't have any written diagrams or instructions but explained the process this way:

1) Remove black resistor wire (part of Blk & Yel + coil wire) from bulk head. In picture it's hard to see but is 3rd in line below RED & BLUE wires in picture.

2) Replace black resistor wire with PINK HEI wire in the bulk head.

3) Splice YELLOW (former + coil wire) that runs to solenoid into the PINK HEI power wire.

DOES THIS MAKE SENSE?

I've read posts here about needing to change wiring on ignition switch...M&S did'nt say anything about that.

["QUICK-SILVER"]

Pretty sure this car has IGN-1/resistance wire and IGN-2/(the yellow crank wire) under the dash. With a single wire from bulkhead connector to coil (+).

IGN-1 and IGN-2 both come off the ignition switch then come together on the inside bulkhead connector.

Clay

[79 Phoenix]

Okay, what do you think that means I need to do?

["QUICK-SILVER"]

I suppose the easiest way is to use the factory coil (+) wire to trip a relay.

Clay

[79 Phoenix]

The guy at M&S said to just remove the BLACK resistor wire coming out of the bulkhead and replace it with the new PINK HEI power feed.

He said it is possible that the car may not start by just replacing the BLACK with PINK. If so, splice YELLOW wire (that runs with the BLACK resistor wire to the + coil) into the new PINK HEI power feed.

Should this work or is there something else I need to do?

["QUICK-SILVER"]

If your car has a single wire from the bulkhead connector to coil (+), that would tell us the resistor wire on your car is under the dash, not under the hood.

Think the tech guy you talked to is thinking about early F-body or chevy.

Clay

[79 Phoenix]

On the new harness, the BLACK wire coming out of the bulkhead has "Resistance"" printed on it... Would that mean the resistor wire is underhood?

According to the 71 Lemans wiring diagram on my shop manual, the solid YELLOW wire joined with the BLACK that connected to the + side of the coil goes to the starter solenoid. The are 2 yellow wires that come out of the bulkhead but they are YELLOW/BLACK and BLACK/YELLOW, but no solid YELLOW.

Also, below is a picture of my ignition switch...Not sure what to make of it but there is a BLACK wire that comes down from the steering column.

[Goatracer1]

Your last picture looks like the directional signal switch pigtail. It is not a clear picture but the ignition switch connector should plug directly into the switch bolted on the base of the column.

[70GS455]

The black wire marked resistance is the resistor wire. You can check with an ohmmeter. If so, pull the terminal out of the bulkhead connector. Splice or solder the pink wire to this terminal and put back in the bulkhead connector

[70GS455]

Originally Posted by 70GS455

The black wire marked resistance is the resistor wire. You can check with an ohmmeter. If so, pull the terminal out of the bulkhead connector. Splice or solder the pink wire to this terminal and put back in the bulkhead connector

admin, please delete

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[HWYSTR455]

Originally Posted by 79 Phoenix

The guy at M&S said to just remove the BLACK resistor wire coming out of the bulkhead and replace it with the new PINK HEI power feed.

He said it is possible that the car may not start by just replacing the BLACK with PINK. If so, splice YELLOW wire (that runs with the BLACK resistor wire to the + coil) into the new PINK HEI power feed.

Should this work or is there something else I need to do?

So yes, just replace the black wire out of the bulkhead with the pink wire and done.

The black/yellow stripe wire goes to the sol, and the solid yellow goes from sol to the coil + side, which was originally combined with the black resistor wire.

That provides a full 12v while cranking. After you change the wire to pink, turn the key on to the run position, and check voltage at the coil. If you see 12v, and it doesn't start, THEN jump the Black/Yellow stripe wire to the pink wire.

I don't see how that combining of wires will make a diff, but it might have something to do with CARB emissions, and a switch may be inline. Or maybe something before the bulkhead inside the car related to the IGN switch.


.

[HWYSTR455]

Originally Posted by 79 Phoenix

The guy at M&S said to just remove the BLACK resistor wire coming out of the bulkhead and replace it with the new PINK HEI power feed.

He said it is possible that the car may not start by just replacing the BLACK with PINK. If so, splice YELLOW wire (that runs with the BLACK resistor wire to the + coil) into the new PINK HEI power feed.

Should this work or is there something else I need to do?

So yes, just replace the black wire out of the bulkhead with the pink wire and done.

The black/yellow stripe wire goes to the sol, and the solid yellow goes from sol to the coil + side, which was originally combined with the black resistor wire.

That provides a full 12v while cranking. After you change the wire to pink, turn the key on to the run position, and check voltage at the coil. If you see 12v, and it doesn't start, THEN jump the EDIT: Yellow wire to the pink wire.

I don't see how that combining of wires will make a diff, but it might have something to do with CARB emissions, and a switch may be inline. Or maybe something before the bulkhead inside the car related to the IGN switch.


.

[HWYSTR455]

Most of the harness companies USED TO offer the HEI conversion already installed on the harness as an option, not sure why they don't anymore.


.

[79 Phoenix]

Originally Posted by 70GS455

The black wire marked resistance is the resistor wire. You can check with an ohmmeter. If so, pull the terminal out of the bulkhead connector. Splice or solder the pink wire to this terminal and put back in the bulkhead connector

If I do that, what do I do with the yellow wire that runs down to (or up from) the solenoid?

Also, could I run the PINK HEI wire through the firewall and plug into the ignition location on the fuse box?

[HWYSTR455]

Not all IGN plugs in box work during cranking, FYI. You have to check.

You can leave the yellow wire alone, it won't hurt anything, like mentioned, it applies a full 12v during cranking only.


.

[79 Phoenix]

Okay, thanks for the heads up re checking the IGN plug. If I don't do anything with the YELLOW wire, isn't hot 12V coming up from solenoid? Should I just stub it off?

[79 Phoenix]

Originally Posted by HWYSTR455

Not all IGN plugs in box work during cranking, FYI. You have to check.

You can leave the yellow wire alone, it won't hurt anything, like mentioned, it applies a full 12v during cranking only.


.

Thanks for the heads up on checking the IGN plug. Wouldn't the YELLOW coming from the solenoid be hot 12V? If so should I just stub it off?

[HWYSTR455]

It would only be hot during cranking, but yes, should cap it off or just eliminate it if you don't need it.


.

[79 Phoenix]

OKAY thanks... I appreciate everyone's help here with this. Just trying to be careful I don't mess up a new wiring harness. I would have ordered one already setup for HEI if I had known it was available. I'll report back in a couple weeks (maybe sooner) when I expect to fire this up.