30th Mar 2012, 19:10

"purchased a 1981 Mercury Grand Marquis wagon with the 351 Cleveland"

Your '81 Mercury would have had a 302 or 351 Windsor engine; the Cleveland was not available in North America after 1974.

12th Jan 2013, 23:50

FYI, the Cleveland engine was discontinued in North America after the 1974 model year. Your 1981 Colony Park would have a 302 V8 as standard equipment, or the optional 351 Windsor V8. No Cleveland in 1981.