they have a Painless Wiring harness for the 302 H.O. from a mustang.
Keep as much of the electronic’s as possible from the efi motor because all the neccesary efi electronics and hook-ups all wire right to the engine wiring harness then hook to the computer. You can make a harness for the starter, all you dis hook pos. from battery to silonoid then a pos. lead to fuse panel - ign. switch - then to small term. on silonoid. Other idea’s would be a 1 wire alternator available at most part stores and online.
Or spend the money and contact Painless Wiring and they will get you a harness for around $500-$600 buck.