289, C4, stock engine, holley 4bbl 12 degrees initial, 34 total... Runs hot when over 85 out... Has had a slight main seal leak and a slight intake valley front and rear leak for a while... also likes to spit out of the valve cover breather on the drivers side... has PCV on the passenger side. That said: Highway... 80mph+ for an extended period... was running amazing. Went to floor it and it started to ping. AFR was in the low 12s, RPM in the 4000-4200 range. Backed off it. Slowed to 65.... floored it (no kickdown) and it was OK until about 80 when it began to ping again. Temp gauge was 85% of the way to the top (stock gauge). Get home... let the car sit. Next day, I come out to oil all over my garage. At least 1/2 a quart. Top of the engine is dry... PCV was 1/2 out of the grommet. Both valve covers and exhaust manifolds were wet, top of the transmission and water pump were wet, breather foam was soaked. Topped off the oil and ran it. Starts and runs fine. Did my intake seals let go? Could this be caused by excessive blow-by from bad head gaskets or worn rings? I run high-zinc oil 10w40 Valvoline. Should I do a compression test first and then sort out getting a gasket kit and go to town replacing everything? So bummed out.