add an electric fan or two..dont forget the 3G alt. if you go that route, otherwise check junkyards for similar mounting larger rads, or some of the coolant additive they sell at auto parts stores, that should help
I dunno about a bigger radiator, but I recently put in a 3-row replacement radiator. It's not a fancy aluminum one, I think it was less than $150.
I'm using the stock fan. I haven't had any overheating problems, and the temp around here was up to about 90 over the summer. Of course I'm using a stock temp gauge, so I don't know what its really at.
i got a couple really nice and cheap copper 3 core radiators off e-bay for less than 95.00 BRAND NEW and a 3.8 V-6 Taurus fan from the salvage yard -- just DO NOT MOUNT THE ELECTRIC FAN TO THE RADIATOR WITH THOSE CHEAP PLASTIC FAN MOUNT STRAPS!!!!! it caused one radiator to fail on me - now I get some metal from the hardware store and bend it in a vice to make solid brakets with good support.
The HD 3 core is popular. But with that big motor, if you're someplace hot, it still might not quite cut it.
Info about your climate and temps your seeing now (with what components) might help. My personal recommendations change depending upon the poster's location (I go one step up for desert inhabitants, etc).
try a lincoln mark VIII fan it was theonly thing that brought my temp down.....also flush your system you getbuild up and it reeks havok on your rad.....I try and do it every spring and get ready for the 100 temp in OK