72 GS 350.....installing a turbo 400....kickdown wiring?

Discussion in 'Sparky's corner' started by Canadian GS 350, Dec 28, 2019.

  1. Canadian GS 350

    Canadian GS 350 Well-Known Member

    doing the conversion from turbo 350 to turbo 400.....I have the pedal with kickdown switch, I have found the wiring and connection for the switch under the dash.
    Where is the wire to go to the kickdown on the turbo 400

    My car is originally 350/turbo 350 car......since it has the wiring at the dash for turbo 400 kickdown, is the wiring at the firewall somewhere for the rest of the turbo 400 wire to tranny?

    Thanks
     
  2. BrunoD

    BrunoD Looking for Fast Eddie

    The wiring for the 400 will not be there,but one wire will,you can use that one wire,just add a ground to it.The 455 harness does come with 2 wires,not the 350.The wire should be with the harness,pink wire?.Not sure of the color,but something close to red.Bruno.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The wiring if it is there will be a Black/White wire, on both sides of the firewall. The gas pedal switch gets it's power from a yellow wire. So the gas pedal switch harness should be 2 wires, black/white, and yellow. The yellow wire is on the same fuse as the radio. This is from the 1972 wiring diagram in the 1972 Chassis manual.(something you should already have)

    KickdownWiringTH400.jpg
     
    Last edited: Dec 29, 2019
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Bruno, you are thinking about the Transmission Control Spark harness. That wire is pink and goes to the vacuum solenoid near the carburetor. See the wiring diagram above.
     
  5. BrunoD

    BrunoD Looking for Fast Eddie

    I hear you Larry,as I always say,my memory is not what it was.Also the part on the driver side of the transmission there's is a prong where the one wire plugs in ,you have to get one of those with 2 plugs,that exxtra one will be for the ground.Bruno.
     
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    The 2 prong transmission case plugs used to be for the switch pitch. In the 70's the extra prong went to a pressure switch on the valve body. The pressure switch was self grounding to the valve body. The pressure switch signaled the vacuum solenoid to supply vacuum to the distributor when the transmission shifted to 3rd gear. His 72 should already have the 2 prong case connector.
     
  7. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Thanks Larry, I do have the manual. As the car came with a turbo 350....do you think the black and white wire is there on the fire wall side coiled up somewhere?
     
  8. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Larry - I will likely end up ordering an engine wiring harness for my 455 turbo 400 conversion......this harness would come with the wiring in question......so all I need to do is a temp solution until that time.
    Thanks
     
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Not sure, maybe on the passenger compartment side of the firewall. In any case, wiring one up is easy. One side of the gas pedal switch gets ignition on 12 volts, the other side goes down to the transmission.
     

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