Oil Pressure/Clattering issues

[scoutcamper]

Hi All,

Some backstory: Steve Van Gent and I(his son) have been building up my 71 stepside for about 2 years now. I was able to track down a "donor" 72' long bed that had a working no-issues 350. When we pulled it out of that 72 we painted it, changed to edelbrock elite series valve covers, put a edelbrock 1406 performer carb on it, and new spark plugs and distributor cap(non-hei), we also picked up a 700r4 trannie that we had rebuilt by the local(reputable) trannie shop. Pics here: http://67-72chevytrucks.com/vboard/s...d.php?t=459267

The engine now in my truck has an interesting problem. When it is cold it has lots of oil pressure, but once it warms up the oil pressure drops to zero. You can get the oil pressure back up by stepping on the gas. The other odd issue is that when it is in Park or neutral(no load) and you rev the engine at all you can hear clattering.

Thoughts? I have been told that this is not a big deal and that the SBC will run forever anyways.

Thanks,
Matthew