A 408 with a 88mm turbo would be nice. lol Seriously it all depends on what you want to do with the car. I would do some small things as J said, for personalization. You know, make it yours. Its an 85(Which was my first stang as well), so I assume it still has the 10 hole wheels. That would be my first change. A shifter if its a T-5, or shift kit if its an AOD. Its carbed too. So that makes some engine mods easy and cheap as well. If you want more power. When you start that, you need to know where you want to end up. So you dont end up buying stuff more than once.