Ok so I got a 96 Camaro 3.8 that I recently purchased. It has a clatter like valves or lifters ONLY when it's first started cold and goes away after a couple minutes. I have no idea how many miles on the engine but I do know it's a used engine the PO had installed last year. My first thought was old motor, oil draining to the pan during the night, but it's been my experience that this causes a low end knock that goes away once it builds oil pressure. Correct??? BTW, I have yet to verify my actual oil pressure. I have heard this same thing on other 3.8's and even have a co-worker with a 3.4 that's been doing this for over a year. (His thought was lifters but new ones did the same thing). I couldn't find any TSB's on this on ALLDATA so I guess it ain't as common as it seems to me.
So, my question is... is this really common and should I really worry about it and, does anyone know the exactly cause and how to cure it. Appreciate all the help.