Cooling issues, could use some advice

I think the grill could use work for more air in. Like hemidart said, make sure the blades are on the right way and wired correctly. I know that some flex-a-lite electric fans come as pushers so you have to reverse the wires AND the blades.

Also try to remove the thermostat and put just an open restrictor in with about a 3/4" hole in it. You need some restriction or else the water will not cool in the rad.

I'm not familiar either with water pumps on LA vs magnum, but it there a chance you're turning the water pump the wrong way? Small block fords changed when they went to a serpentine belt and it rode smooth side of belt on pulley therefore turning it counterclockwise. Guys would put a newer motor in but use their old pulleys and run into lots of issues.