Pull the distributor and remove the valve covers. Spin the
oil pump with a socket and extension (tape the socket onto the extension) does it have pressure now? Is
oil coming out the tops of the pushrods? It may even be that the bypass plunger in the
oil pump is stuck open. Or the pump is not getting turned by the dist. Check the hex drive on the bottom of the dist shaft for wear, same goes for the oil pump drive rod, they can even break. The oil pump pickup may have broken, cracked, or come slightly loose from the pump and allow it to suck air instead of oil. The pan does have adequate oil in it, right? Don't run the engine until you find the problem, I am hoping for your sake you are mistaken about oil in the sidepipe, maybe it's just soot running out with moisture or gas.