I recommend buying absolutely the biggest radiator you can possibly stuff in there, even if it means drilling new mounting holes. You can't have too much radiator! When shopping for an aluminum radiator, look for fully welded/brazed (no epoxy), wide tubes (the wider, the better), and personally, I wouldn't go more than 2 rows.
A high volume water pump is a good idea, either mechanical or electric.
On the subject of fans. If you keep a mechanical, make sure you have a good shroud that is sealed to the radiator. Fan blades need to be half in, half out, or thereabouts. If you go electric, SHOP FOR THE HIGHEST CFM. With that, comes high amp load, so make sure your alternator is up to the task. A 60 amp square back from the good old days won't cut it! Consider an OEM fan assembly. I use an electric fan assembly designed for a '94-97 Ford Thunderbird. It has a 2 speed motor. You can buy them new from rockauto.com for less than 80 bucks and they move a TON of air! It requires a thermostatic controller. I use the model 2sp from Delta Current Control. Quality is very good.
http://www.dccontrol.com/relay_controllers.htm 
