Switching ECU'S
 

Would an 86 NA ECU work on an early car (84).

Yes, but I believe that you would have to put in a newer AFM in as well.

yup. AFM and the DME (what the ECU is called on these cars) need to be same generation.

have an 86 ECU and AFM in my car now. Its good to do if you track the car because yuo can chip it easier with better chips. It also stops the "idle stumble" on the early modles where you rev the car and then drops to 600 RPMs, latemadels dont do that.

Any other benefits to adding a late ECU to an early car besides chipping and idle stumble?

removes weight from your wallet so you go faster?

lol...