[Joules]

The first letter is the decade wher 'E' is '80's, the second digit should be a number, hence could it be '9' in your case? If so it is a 1989 block. Third digit is product line where 'Z' is Mustang and fourth digit is Ford service part designation where 'M' is Ford Motorsport SVO. The number 6015 is Ford's basic part # for an engine block. Then the next digit should be a letter indicating revision and finally 351 is CID.