Car getting real hot....

All engines with a proper cooling system will do the following:

1. After the engine is warmed up and at speed (30 to 45 mph or better) the engine temp should be about thermostat temp.
2. Slow down in traffic, the temp will rise but at some point it will level out.
3. Shut off the engine, the temp will rise, no water flow past the temp probe,
4. Start engine again and the temp goes down.

Question for all, is 1500 mile's on a rebuild enough to break it in
My understanding is a newly rebuilt engine will tend to generate more heat than after it is fully broken in.

I have to assume from what you have said the existing rad fan and shroud cooled the same engine properly before the rebuild. Correct?

Of the cooling system the only part you replaced was the water pump. Does it have the same number of vains, same length, pitch depth etc?

All the above advice is spot on.

A quick check would be to let it idel on the driveway, keep monitoring the temp with a know good measuring device. If the temp keeps rising and you get to 220 you have an issue with your cooling system.