1970 Dodge Charger oil leak

I have a 70 charger with around 1000mi on a complete rebuild. Its a project car so It sits for long periods of time in between starts. I recently started it after I cranked the engine with the coil wire off to splash some oil around in it. It started, it ran good, I reved it a little with no ill effects. It did not leak oil or seem to have excessive oil pressure. The next day I started it up and was going to check the timing, I reved it up like you would checking for carb bogging, or throttle response, thats when it leaks oil from somewhere on the left side of the engine, only at higher revs, doesnt leak at idle, idles good. Is the oil pressure relief valve stuck closed? Or do you think I broke a piston ring?
Like I said it started and ran good with no leaks the first day, If I broke a ring wouldnt it have leaked the first day after I started it? It seems to be a pressure related problem.