I recommend contacting the guys at PerformanceRadiator.com and asking them. I have found good luck using the Super Cooler (part number 1502). Its not aluminum, but its best radiator I have owned. I first bought a super cooler from them when I was in Tucson, AZ and I have never had a cooling problem since. They have shops all over the US, so find the one closest to you and give them a call. note: their website is down for upgrades until the first of the year.
1972 F-250 4x4
1975 F-250 Crew Cab 4x4
1976 F-250 4x4
1977 F-250 4x4 High Boy (VIN:Y20821)
1979 F-250 Crew Cab 4x4