I had a Champion 3 row, and the threaded bungs for the transmission cooler lines were incredibly loose (0.46" diameter when it should be 0.45" for female 1/2"-20 threads). The type of loose that makes any experienced amateur mechanic believe whole heartedly that they're going to strip when you're looking to tighten the tube nut to stop a leak. It freaked me out because I'd never seen a fitting that loose before. I found a maximum torque for aluminum to be 328 in-lbs (27.333 ft-lbs). I torqued a tube nut to 20, 22, 24, 26, and then 28 ft-bs without the threads stripping. However, I wouldn't recommend Champion. I'm convinced that it was the TIG welding that permanently expanded those threaded bungs.
This is the radiator that I purchased on Ebay, except in the 3 row version:
https://www.alloyworksplus.com/produ...dex.header_1.1
...and the thread bungs were much smaller in diameter and fit a 1/2-20 tube nut just fine.
With any of these so called "direct fit" radiators, you're going to have to modify the supports somehow. The only ones that have the "rib" that fits into the rubber support are Be Cool radiators.