Yeah it is a pain to get through the ref but the ref's know exactly how to get through. They usually are pretty helpful, too. If you make an appointment with them, they will check it out and tell you want you need to do. When my 5.0 swap went through the smog ref they said it needed a change to the vacuum system but that was about it. My 5.0 was a complete drop out 1990 5.0HO in an 89 Ranger. It was hooked up in my engine bay like an 1989 5.0HO but 1990 5.0HO vacuum routing was slightly different... hence the change.
Generally speaking, when they inspect it, they will tell you it needs to have all the CARB legal parts for the original vehicle it came from. So if you have a header with a CARB number for 85 T-bird you may be OK but if you have an aftermarket header (no CARB number), you will probably need to get a factory manifold to get your smog sticker. Some of their sticky points:
1) Make sure you have a CARB legal cat for an 85 turbo T-Bird installed where it would be on the T-bird. What I mean is, if it's on the down pipe on the T-Bird, it needs to be on the down pipe in your Ranger. If it was after the down pipe, before the muffler on the T-Bird, it needs to be there on your Ranger. If the T-Bird had air injection in the cat, your Ranger has to, too.
2) Make sure your computer is an original Ford 85 T-Bird computer (pull it our and verify the codes on the sticker)
3) Make sure you have, either, the stock breather on it, or a CARB legal intake for an 85 T-Bird
4) make sure if passes KOEO, KOER, and Cylinder balance tests before you go
5) Make sure EGR, EVAP, vented gas cap, smog pump, and PCV are installed and working (if 85 T-Bird hard them)
here is the link to get to a ref
Ref Link here
Once you get through the ref and get your smog sticker on, smog is never really an issue again. You basically smog it like an 85 T-Bird from then on out. You get a notice in the mail that is it due, so you go to any smog station, tell them you have a ref sticker in the door jamb, and they do their thing; no extra costs, no special inspection, etc.