Small Block & Big Block Chevy Specific - 327 advise

I have a 327 in my 69 nova but when it heats up it seem to loose oil pressure and bogs out big time...please all advise is needed.

What are your gauges reading? Has there been a major change in oil pressure lately? Is the motor running hotter than usual? Any new sounds coming from the motor?

Is this a rebuild? My 68 camaro was 100 stock untill this summer. It leaked oil and seemed sluggish. I pulled the engine thinking I would reseal it, then.. Wham. Found out the timing chain was touching when I pulled inward, the cam had 5 lobes wore off. Having bad cam bearings will cause oild to go away when it heats up. Im sure if its never been touched you will need a oil pump and chain.