the small driver's side fitting is 1/8" pipe thread, for the stock electric gauge sender. The large passenger side fitting is probably 1/2" pipe thread for an aftermarket mechanical gauge adapter. The last 2 passenger side fittings are 3/8" pipe thread, the "upper" one is the heater return and the lower is the pump to heater. The fitting that goes in the lower pump to heater opening will probably interfere with that allen head socket bolt holding the pump housing on, you might have to repace it with a regular hex head bolt. I would think you can get the fittings from any resto place if you are going that route, if not, your local auto parts store probably has something you can use in the "help" (motormite) section or maybe they can order them through Standard/Four Seasons. The fitting that goes in that lower hole should be pretty tall (maybe 2 1/2 inches or more) otherwise it is almost impossible to get a hose/clamp to fit in behind the alternator bracket. Hope this helps....
