i see what ur saying now, i don' believe it will plug up because thats what the whole conversion harness is for, i'm not %100 percent sure if it will or not at the firewall tho. what i would do since the car is obd1 is get an obd1 engine harness and dizzy, if you do keep the obd-2 harness your going to have to rewire the dizzy for obd1