Big block + large rad + Mechanical fans = what fits?

All I can say is with the 69 factory set-up I am running it is just fine. Look up the factory parts, they work when all the components are in good shape. A bigger flow pump and t-stat will help. I do not think if you get a Mopar clutch/thermo unit it will fit the A-Body stock BB set-up! I am using an 033 68 radiator but the demensions are the same.