the tip of the spark plug was oily? can you see lots of residue on the pistons when you pull the plugs?
the engine is likely toast simply from driving with 1.5 qts in it. probably time for a rebuild reguardless.
Droste Drummer. Droste like Frosty.
00" Red ZX3: Volant, ported throttle body, titanium wrapped SVT header, 2.5" exhaust, Magnaflow res/muffler, FR UDP, Mac cam gears, Lowered 2", Koni's.