Why motor starts running rich & backfires

Same person

I never got answer to my first question

If you over-filled to so much that the crankshaft dips in to oil in pan, it will whip it in to a foam like a blender. That will cause no oil pressure and even break down oil. Drain and fill to proper level.... find the spec for your engine capacity and put in that much oil minus ½ quart. New oil filter. Backfiring through exhaust or back through intake? Backfiring from exhaust is raw fuel exploding when it enters cat or muffler. I don't know if in 1984 they still put carburetors on El Camino's. Check/set ignition timing, and if it backfired up through intake new air filter. It may be so clogged is why it's running rich, especially if you are blowing black smoke.