Cooling issues, could use some advice

Is the cap now on a surge tank, or is it on one of the main hoses? If it is on one of the hoses it's rated pressure is reduced by the coolant flow.

I don't trust any of the chain store water pumps. I'd put either a Milodon or an Edelbrock pump (are there other MOPAR app. mfg's?) on the short list.

On the Boss 302 R.E.D. that I crewed on years ago the owner/builder just had a 10' long coil of copper tube for the trans cooler. Obviously we didn't drive that car back down the return road.