put together a 427ci(396block)with mech flat cam, not properly broken in so we wiped a cam lobe. ok, reboot, take apart eng have hot tanked with new cam bearings.purchased a hyd roller retrofit cam with lifters,pushrods,roller chain and cam button. sent heads to shop and springs were ok for new cam.replaced oil pump and screen(took apart pump staked gears, reassembled)set preload on valves at zero plus 1/2 turn. note: cam plug also replaced 40wt kendall primed and started.***** two minutes later noise started, not a knocking sound, not a whining sound, more of an _intermittent_ combo of a chirpping,rubbing. stopped drained oil, no metal new oil 40 wt  valvoline apprx two min noise started,same noise friend suggested oil pump let run longer, no metal. changed dist gear to bronze same noise checked starter clearance(just because) noise is lowe end and will verify with mechanics ear tonight, just hoping someone might have a suggestion, if not we will pull this out tomorrow  

What year is the 396 block? Early 396 blocks used to have a groove ground into the rear cam bearing for oil flow. maybe that's your problem, rear cam bearing!  

there were two of us putting this together and when i dropped the tranny i found the cam plug well(too well)seated upon removing it i found where the noise was coming from. the cam was rubbing. still no metal was found until i opened the filterso good thing we dropped it . will now wash reassemble and go racing