I used a Plastic Tank Aluminum upgrade on my K5. I forget the number. It's a thick 2 row aluminum core that surpasses the cooling capacity of a 4 row Copper Brass rad. My fan unit is from a Ford product of some kind, though I'm not sure what. I wired each through a separate relay so I could run one at a time if I wanted to. In 30 degree weather if it's pointed into even a light breeze you don't even need the fans. If it does get up to 220, You can cool it down to 180 in a couple of minutes.