As has been mentioned, the 7 row core will fit using your existing top and bottom tanks. Number of fins/inch and the dimples improves the heat transfer.
Make sure the torus drive works properly. . . Several may disagree and recommend a straight drive, but if the torus is healthy?
Some folk have replaced the fan with a similar diameter but more blades. . .
Make sure the fan shroud does it's job - no places around it for air to escape. The fan should suck all the air thru the radiator, nothing from around it. There have been posts by GM and MCI owners about gaps causing problems. . .
Also, since you tend to stay in warmer climates, freezing is less of an issue. Therefore, you might consider using a 60/40 or 70/30 water/coolant mix ratio to improve hot weather cooling. As you probably know, straight water cools the best, but rust becomes an issue quickly! So you've got to maintain some ratio of coolant to reduce the crud factor.
Just some more trivia for you to ponder!
FWIW & HTH. . .