Rebuilt 400 SBC Overheating Issue

[72k20Farmtruck]

I just rebuilt the 400 in my 77 C10. Here’s the specs: Bored .060 over, stock bottom end bearings, trick flow 195 aluminum heads with 3 out of the 6 steam holes drilled, comp 292 cam with .501” lift, I verfied headgaskets are indeed correct. Ran the motor today and it kept overheating. We tried two different t-stats, a 195° and a 180°, still overheating, then ran without the t stat, overheated again. Checked the oil no water in the oil, no oil in the water either. What else could it be? My dad thinks the parts guys gave me the wrong water pump, maybe i have a pump for a serpentine setup and it’s pumping backwards. I don’t know what else to think and I’m pulling my hair out trying to figure it out. It’s the second motor I’ve built, first one without any guidance so if anyone can think of something that i may have overlooked during assembly please chime in. Thanks!!