After replacing the thermostat on a 496 Mag, specifically how do I add antifreeze and completely purge air out of the heat exchanger before starting the engine?

It will do it on it's own there is a hose on top that goes back to the reservoir

+1

You will hafta run engine and watch level and top off.

Fill cooling system thru reservoir to full line.
Start engine. Run at idle until normal op temp s reached. Keep an eye on temp gaugehen doing this. Merc states front of engine should be higher than rear to aid in bleeding air and only ran at idle. As air is dispersed from the system you may have to add additional top off coolant to the system after the initial fireup.

Thanks for all replies. Appreciated.

I'm assuming this same process works on any merc closed cooling system?