Pull the cap and see if it's moving coolant, years ago had a big block that constantly overheated, Pulled the water pump and the impeller was laying in the housing, HMM wonder why it was getting hot.

Start with the basics and collect data, analyze and report back. if it's getting that hot after a drive around the block the problem should be readily apparent, IE: stuck thermostat, plugged radiator, collapsing intake hose, plugged radiator hose (think shop rag, incorrect fan, incorrect pulley ratios, extremely lean etc.
Collect the data, keep it simple and report back