ticking like a sewing machine

bought the duster in Medina Ohio. it was supposed to be a street strip runner.
i used a broom handle to listen to the tick and it is louder on the drivers side but not the exhaust. i will pull the valve covers and go from there. my buddy that did some work on it seems to think that a bearing may have let loose because my oil pressure is not as steady as it was before the last oil change 2 weeks ago. when he drained the oil it was gray/silver and the filter was unusually heavy and the oil was changed 2 months before that. starting at step 1. thanks