wiring options 73 with hideaway headlights/ MSD ignition/electric fuel pump

[73charger440]

Question ive been digging through the half dozen wiring harnesses I have, the question I have would it be easier to Frankenstein a wiring harness together with all the strange options I want or start from scratch withs a new harness .its a 73 and this would be all the add ons to the harness hideaway headlights/ MSD ignition/electric fuel pump, anyones whos used aftermarket eiring harness give me your feedback on how it was

[Nacho-RT74]

Hideaways, there is a guy on ebay selling a full set ready to install for it... not cheap. Its easy to built actually. This harness doesn't have realtion with engine harness and runs parallel to the forward light harness.

engine ( MSD and electric pump ), piece of cake to make from any regular engine harness

[ottawamerc]

  I did all those to mine too not a big task.

Scott

[73charger440]

Ok sense I'm going with the MSD ignition and the voltage regulator due to the new one having an internal regulator ?what would you suggest doing with the orginal wiring? I'm trying to figure what wiring to keep, I wouldn't just cut it I would untape and pull it out at the plug

[Nacho-RT74]

depending... do you want to keep stock look ? What would be the MSD location ?

Ballast can be still in place because the coil signal ( brown wire to + lead of coil ) will become on the ON/OFF switch to turn on the MSD module. Doesn't matter if goes through the ballast or not. Any voltage signal is able to turn on the MSD module.

If you STILL want to be sure the MSD gets full 12 volts to switch on the MSD module, and STILL keep the ballast look on firewall, you can get removed the resistor from the back of the ceramic piece and replace it with a jumper wire between prongs on ceramic groove.

If you don't want to keep the ceramic piece, simply splice together blue and brown wires arriving to ballast ( coming from firewall ), and splice there the thin red wire from MSD, which is the on/off wire.

IF you will keep the stock module location to install the MSD, you can simply make any of the jobs mentioned BUT cut the stock ECU plug and:

Use the Blue traced yellow wire to feed the thin red wire ( ON/OFF signal ) instead use the brown wire arriving originally to coil. OR instead run the thin red wire into the existan blue and brown wires from ign switch if you remove the ballast setup.

Use the wires coming from dist up to ECU and splice there the MSD distribuitor signal wires.

Green traced red and black traced yellow from ECU plug will be unused, but can be simply isolated and hidden down the tape.

This idea will make use the existant wiring instead run through the engine bay extra wires from end to end.

MSD provides the wires to coil in a separated harness so nothing to do but simply run those wires. Original coil wires can be simply isolated and hidden down the tape to harness.

Some of the stuff I told you will allow you to reverse the installation easily or not depending on yout own choose. You can also remove old tape and built your own harness per MSD instructions, "retaping" the modified harness.

REGULATOR... can keep in place or not, is up to you. Alternator end will be used or not depending on the alt you will use. Usually they get the ign key signal, and the blue wire is the one for that. Green wire will be unused. Black thick one will be still the main one on any alt setup.

[Nacho-RT74]

I can get you diagrams for EVERY OPTION described on sunday. ( lot of job up to saturday )

[73charger440]

That's great man !! That helps a lot ,I'm going for a non stock  look and am trying to go with Simplicity as far as the wiring.would you have any suggestions on cleaning the wiring up there's 40 years of grime and the connectors are pretty nasty

[Nacho-RT74]

let's start to let you know how is your original harness.... this is a diagram I already had made... will modify this later to every setup posible I described. ( colors are close top originals )

Tach wire actually could run through the firewall with a grommet... AC system ( compressor ) could use this cavity for that use.

[Nacho-RT74]

Need to know where you will mount MSD module and if will keep stock distributor

Then also specifically what alternator and MSD module will use

[73charger440]

http://m.summitracing.com/parts/msd-6425. MSD box

http://m.summitracing.com/parts/sum-812106 alternator I thought it had an internal regulator but it does not

http://m.summitracing.com/parts/msd-8546.  MSD  distributor
And as for the mounting it's been so long sense I've taken this thing apart not sure where the stock location is for the ignition but it kinda looks like the area on the pass side by the hood hing would be the easiest any thoughts nacho ?

[73charger440]

Stupid question what is the function of  porcelain ballast ?

[Nacho-RT74]

The resistance changes the voltage depending the engine temperature and the load requested by ign system. Mainly the coil to protect it from heat due unnecesary electrical to burn the gas already heated by the engine, variating the voltage. This ballast is protected by the porcelain housing.

sorry it took so long, will work on this this afternoon.


Sure IMHO, the stok ECU location works good for the MSD too. A bit tight, but there is room.

Alternator is nothing more than a stock alt 60 amps but chromed... go to tuff stuff website and get a better output unit, or simply get a CHEAP 78 amps replacement from earliers 80s Mopars. The idea is get an alt able to give at least around 50 amps iddling. A 60 amps unit will give you that at around 1200 RPMs

[VegasCharger]

That's great man !! That helps a lot ,I'm going for a non stock  look and am trying to go with Simplicity as far as the wiring.would you have any suggestions on cleaning the wiring up there's 40 years of grime and the connectors are pretty nasty

I've got a real nice OEM wire harness from a 1973 B Body with rallye dash. Complete under dash rallye dash wire harness, no corrosion, no hacks, no burns and no splices. Even the Bulkhead red/black cavities are nice as well as the fuse box. No melted ports. AZ car most its life.