oil consumpotion

Hi engine gurus...
2 weeks ago I had an overheating problem on the Autobahn cause the radiator hose broke... The engine ran hot ( 220-230°F )for a few seconds.
Yesterday I drove back from a mopar meet and after 200 miles I lost abot 15 psi oil pressure (normally 55psi at all rpms). As I checked the oil level I saw nothin on the dipstick. I filled about one quart and had constant 55psi. Next 200 miles same story.
Engine (340) is rebuild 1,5 years and 2500miles ago. Never raced... (exept a lil Autobahn).
I didnt checked anything so far but what do you think? I have no noises, no performance loss, no smoke at the exhaust (as I can saw so far in the rear mirror) and no wet block...
What would check first? Valve stem seals....?

Michael