A similar question came up on
www.foureyedpride.com recently when someone asked about keeping the original dash in a Mercury Zephyr Z-7 with a Mod Motor. When I did mine, with an '88 dash in a '79 Futura, there were no conversion kits at the time so I stripped all the wiring forward of the firewall, used the Mod Motor wiring under the hood, and connected it with a homemade harness (see pictures in the Electrical Wiring section, "Wire Harness" dated 5/19/2010) to the '88 dash. If you can get a kit, great, but cutting up the Mod Motor wiring to make a stand alone harness and matching it to the existing wiring is a major task IMO.
If you're using an '86 or earlier dash with a Mod Motor, the sending units for temperature and oil pressure on the Mod may not work with the earlier dash. All the Foxes from '78 thru '86 used gauges that weren't volt meters but rather a bi-metal coil that either wound or unwound depending on the amount of current going thru it. The gauges were also controlled by a voltage regulator in the dash, and my experience with them was they weren't very reliable. I once had the oil pressure, temperature, and gas gauge all peg to the high side in bumper-to-bumper traffic on the New Jersy Turnpike.
Regarding disabling the PATS system, I had it done on mine by The Detail Zone in Wilmington, DE and it doesn't affect operation of the engine at all. I also need a special speedo cable, probably 18 to 24 inches longer than stock, to clear the cylinder head and reach to the sending unit on the T-45 trans.
