I would without question put in the biggest radiator that would fit. Get as many fins per inch as you can. Makes a big difference in the cooling capabilities. Preferably a aluminum 3 row. Add some Water Wetter by Redline, about 2-3 bottles and enjoy. I would not run a high pressure cap. Use a 9-11 lb cap. For every pound of pressure you raise the radiator temp 2 degrees. Also Prestone makes an irridecent green additive that works good like the Redline. I use either and have very good results. Not snake oil or a gimmick. I live in a Hot summer climate. 90s to over 100 degrees. It makes your antifreese remove the heat faster as it goes through the radiator. Have fun! An large cooling fan may be necessary but with what I suggested you should not need it. Kind of a last resort type of thing. One other thing, they do make a High efficiencey aluminum water pump thats moves more coolant. Not cheap but with what you have already spent, it won't be too bad. They do really work even on H.O. racing engines. Don't forget the shroud if you can put one in there. Don't use those super small blade fans. They look cute but don't work very well especially in traffic or on V8s very well. Seen several of them. Good for a high rpm ( Jap crap ) small motor perhaps but I would not put one on my V8s that I have. Get a REAL fan if you use one. 5 or 6 blade full size.