Pull the valve cover and check for broken valve springs. Also, while the oil pan is off, drop the caps off the rods one at a time and inspect the bearings. Ditto for the main bearings, although if you remove the rear main cap you'll probably have to replace the oil seal. A bad bearing doesn't always show any outward signs until it's really in terrible condition. Losing oil pressure is usually a sign of excessive rod or main bearing clearance.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!