I have a 88 with a 22611-aa520 in it will a 22611-aa320 out of a 87 work?

Unless someone else pipes up, I'd get one from 1988-1991. PM or email me, I probably have one.

 

I tried a conversion/swap of a mid year 1987 model and found that the 1987 year can be a complicated one with a few wiring differences. It's the car in my signature, I'm still working out bugs with it and if memory serves me correctly (been awhile since i've tinkered with that annoying project) the 87 and 88 years have slight wiring differences. I was trying 88+ ECU's and ended up looking for an 87....but my issues were slightly different than what you're asking too.