My son and I are putting his car back together. We got it in many baskets. Car was running or had run when parked before the previous owner stripped off the plug wires. We transplanted a 67 390 and C6 with headers. Car will run power steering also. We are sorting out the wiring and just purchased an engine gauge harness from a mustang vendor and the wires all are to short. We told them it was for a BB. This is the flat 3 wire connector by the fire wall. Beside it is a 4 pin squar connector with 2 males and 2 female terminals. Where does this go?