Re: How do I clean out the mud that used to be oil ?
If you're sure you've got anti-freeze in your crankcase don't drive it if you don't have to. Ethylene glycol is poison to oil lubricated parts. If you can find it locally flush your engine with "butyl cellusolve" after draining the bad oil. As a GM employee during the mid 80's I've seen wholesale what coolant contamination can do to engines; the early Cadillac 4100's all had coolant contamination issues and the customer's first clue was almost always a miss or backfire caused by one (or more) failed cam lobes. These folks had the benefit of a warranty and a very embarrassed GM. If nothing else I would change oil and filter, drive or run the engine in place long enough to get good and warm and change it again. Oil is cheap. Good luck.
76 CJ5,2.5" lift/Rancho 9000's,258/T-177/D300,HEI,Offy,Locked F&R