New motor blowing oil on headers

Bob is right, do a leak down test on it. Then you'll know where you're at. When I assemble my engines I leave the bolts on the timing cover loose and install the damper. After the damper is fully seated and torqued I then tighten the timing cover bolts.

IMO if your rings weren't seated by the time you drove it the first time they never will seal. If you have room under the hood for a carb spacer you could drill and tap it for the PCV. On the dyno my 434 small block made 13 hp more with a 1" Super Sucker spacer and 3 more hp with the pcv valve hooked up.