Found my dads original 1971 duster!

So I’ve just swapped thermostats. I was hoping something was wrong there, but no luck. It already had a 160 degree thermostat that was in the proper way-with a vent hole (first and 2nd pics) tested it and the one that I put in to replace it. Both function properly. 3rd pic is new one I put in. I drilled a hole in it, as instructed

I guess next step is making a spring out of a coat hanger for the bottom rad hose. Then test for temps

I forgot to fill the block before I put new thermostat in and tightened it down and put hose back on. Is that ok? Rad will fill it once I start the car? I only drained the rad from the drain spigot on bottom, so I’m assuming it will be fine. Thanks