340 with edelbrock heads overheating

Early a body said
when i am driving it will maintain the temperature it was at while at idle. It will not cool down. I am going to try a water pump next. I ordered a high volume one from summit. if this does not cure it off come the heads.

i guess its possible there is some sort of obstruction in the cooling system somewhere. Not sure if doing a coolant flush will help at all.

i used felpro head gaskets. What head gaskets is everyone using when swamping to aluminum heads?

Before removing the heads I would verify the thermostat opens properly. Suspend the therostat in a pot of water and use a thermometer to measure water temperature when the thermostat starts to open. You have to have it hanging so you can see it just coming off its seat.
Start with inexpensive and easy tests first. Remember Occam's Razor and Murphy's Law. And then KISS.