85stang306

just got a 1995 thunderbird and in doing the routine maitnence fuel filter,oil, ect ect i was changing the spark plugs and on the drivers side cylinder closest to the radiator pulled the spark plug fouled of coarse but was soaked in oil i was thinking cracked head possibly bad rings but theres no oil burning in the exhaust just wondering what any one was thinking cuz if it needs rebuilt then im putting a 4v in the car. Reason being my buddy has a fresh 4v motor he will let go cheap with only 1500 miles so any imput would be greatly appreciated.