1989 5.9

I would grab the entire wiring harness, including the dash harness., all sensors trans controls everything on the engine. Be aware if you go with aftermkt fuel sys. and ignition, it is much simpler wiring - BUT the AC thermistor, fuel pump safety cutoff, purge canister, trans kickdown, lockup, fans. etc. are all looking for input/output from the smec and the tbi sensors. Took me almost four years to debug all this on my 89 Shelby Dak. The LA roller engines are wonderful build basics. Good luck.