Yes should work fine, the a9l is a five speed mass air computer. All u have to do is move some wires and plug them in. Don't forget to take the vacuum line off the map sensor next to the vacuum tree on the driver side. I think it's a BAP sensor on non mass air, but once it's unplug it will be a MAP sensor.
Let me clarify a little better. The pro m harness should work on the factory harness that's already connected to your computer now on your 86 if it's a efi car. If its the last year of the carb then u will have a lot of wiring to do.