I recently blew my 2.5 in my 98 ranger. I was wandering if I could replace it with a mid 80s mustang 2.3. If I can what modifications will i have to make in the electronics?

 

Find another 2.5L and make this easy on yourself.

If you go with the Mustang 2.3L, in NA form, you lose about 40 hp's and sensors are in different places on the block, I'm sure, thought they might be able to be fiddled with.

If you want to go the SVO turbo route and transplant that into your truck (I hope you meant that at least), still find an SVO turbo in as good a shape as possible and drop it in.