Slant six w/points to V8 w/electronic

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Gryzynx

Gryzynx

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I'm in the throws of my V8 conversion. Swapping in the entire K member/318/disk brakes from my 74 Dart parts car replacing the /6/drums in my 68 Cuda. Didn't find a thread on this, so I'm going to document it here. Probably should start a build thread, but this one will cover wiring.

Wiring diagrams at http://www.mymopar.com/index.php?pid=24

Wiring in both cars is in pretty good shape, so I'm going to reuse the stock harness. The firewall plugs all fit, but there are some wires which need to be moved. There also is the matter of the electronic ignition and regulator and there seems to be an issue with the starter relay and neutral safety switch wiring.

I will reuse the entire underhood wiring from the 74 Dart. I'll remount the components in the positions found in the Dart. Might make an exception to the windshield wiper plug.

Here's a list of the wiring changes I'll make at the firewall plugs. I'm referring to the letters in the wiring diagrams from the mymopar.com link.
All the wires can be released from the plug body and reinserted to the new destination. Should not have to cut anything. All references are to the 74 harness.

Swap wires L and T (horn and starter relay)
Remove black wire from Z. Tape it up, it will not be used. (74 backup lights) Same circuit also feeds C, which is correct for the 68.
Move U to Z (marker lights)
Move M to W (brake warning light)
Move W to D (power for B/U and neutral safety switch).
My car does not have an electric washer pump, but I may add the one from the 74 and I will power the motor from D

All accessories from the 74 will be used under the hood including the ballast resistor. All the 68 accessories will be removed.

I was concerned about the electronic ignition and voltage regulator, but all the necessary wiring is in the 74 harness and it powers from N and Q on both cars. Should be plug and play.

The starter relay is an interesting problem Be sure to reuse the 74 starter relay. The 74 and 68 relays do not appear to interchange. The earlier relay uses a ground switched thru the neutral safety switch to enable the relay, the later relay uses battery + thru the neutral safety switch to enable the relay. Also uses this power to light the B/U lamps.

I'll post a follow up if I've missed anything. In the meantime, anyone with experience on this, can you find anything I've missed, or got wrong? Thanks,
 
The wires in the 68 good? If so why are you changing so much??

Why not just add the electronic ign and dual fld wiring to the 68 harness? It's cake to do. Only a few wires. That way you can use your stock starter relay and all.
 
I did this same thing, and it was cake to do. I'm by no means a genius mechanic either.
 
abodyjoe said:
The wires in the 68 good? If so why are you changing so much??

Why not just add the electronic ign and dual fld wiring to the 68 harness? It's cake to do. Only a few wires. That way you can use your stock starter relay and all.
Click to expand...

Thought about it, may try this.

Looks like I can sacrifice a V8 underhood harness and if I can keep all the proper circuits intact, I'll have a harness that should plug into everything with a brown and a dark blue wire which will go to Q and N respectively. If I work this right, I should be able to make these connections at the original ballast resistor location, thus minimizing the amount of splicing. That should take care of the electronic ignition and voltage regulator. I'll have to modify the oil pressure and temp sender wires cause they are in different locations /6 to V8. I'd also have to change the neutral safety switch on the V8 trans to the old style switch. Upside, no messing with the starter relay, downside, I'd still have to dress the new wires into the original harness to make it look right. Also should remove the original ballast resistor/coil wiring and the regulator wiring.
 
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