Please help me diagnose an overheating 283

[fourspeedwagon]

So— this isn’t in one of my pickups, it’s in my ‘57 Bel Air.
All stock 283 power pack. I’ve had it for a couple years and I knew the radiator leaked so I thought that was why it’d heat up. Last year I had the radiator completely rebuilt but of course Nothing happened last year and I don’t even remember taking it out.
The other day I took it off the battery tender and put a couple gallons of non ethanol in. Fired up easily and after I had my wash buckets ready I decided to take it around the block before cleaning it up. I watched the temp gauge climb and circled the block (a country block so maybe 2) and when I got back home it puked a bunch of antifreeze onto my driveway. After it cooled I put a new 180 thermostat in. Didn’t help. I called the radiator shop that redid it and left a message. Guy called me while I was at work and said I should check the temps at different spots with an infrared thermometer. I did, but of course they were closed by the time I got back and could call them.
A couple minutes warm up and a trip around the block gave me these temps:
Top tank of radiator 160 degrees
Bottom of radiator 125
Water pump 225
Top and bottom radiator hoses were hot to the touch but only showed 160 or so I think because the rubber didn’t heat as quickly as the metal.
I turned on the heat in the car and it was working.
When I turn off the car it “diesels” or runs on.
Outside ambient temp 65
I backed off the timing a bit and didn’t notice a difference either.
My thought is water pump but the heater putting out heat is causing me doubt on that.
Thanks for your help. It’s not one of my pickups but this is the forum I frequent- haven’t found a tri5 group that I fit in..