I used a $160 parts store replacement radiator from my 2006 Yukon donor, including the donor fans. 34 inch core. Fits great. Cheap. I can go into any parts store and get replacement parts including all of the various cooling hoses.
I wouldnt have hesitated to use my factory radiator for the truck, but it was a mostly clogged 6cyl radiator and didn't keep the 350 that was in the truck before cool at stop lights.