http://www.ebay.com/itm/NOS-1980-1986-FORD-F100-F150-F250-F350-300-4-9-ENGINE-GAUGE-FEED-WIRING-HARNES-/141202691091?pt=Motors_Manuals_Literature&hash=item20e0561413&vxp=mtr#ht_199wt_867

 

Not cheap, but I paid $117.00 for mine three years ago.

 

That's a little pricey considering what you get; also one of the connectors in the picture needs to be replaced. You can buy the female connectors and horseshoe coil connectors separately and solder/shrink-wrap everything nicely with primary wire. The harnesses are also not too tough to find at a pick-and-pull. It doesn't make any sense for the harness to cost more than a top-of-the-line Motorcraft ignition module.