First off, you do not need the ECM. It does not control any of the power options in the car. It used to control the carb., dist., and the TC lock-up on your car. Which you already said that you have the non-CC dist. and carb, so the last thing (TC lock-up) will not be that big of a thing.
Take out the old wiring harness as stated above, but leave the Transmission plug still intact. You will need this to Fab a switch to manually lock-up the TC. There is a Tech. article on this if you need it.
Also if you have electric fans, make sure you dont delete, ie. cut the wire that supplys power to it or them.
89RS-LS1/Th350/4.10/NX200 1.54 60ft. 6.70@103