A '74 Montego MX is a rare find indeed - there were only about 21,000 made that year, and thirty years later I would guess that less than 20% are still around. Hold on to the car, especially if it is in good condition and has not been modified, it will only increase in value. As for interchangability of parts - all 1972 through 1976 Ford Torinos and Mercury Montegos share bodies, chassis, interiors, engines, trasmissions, etc. In short most parts are interchangable between the two car lines. Also the 1974 through 1976 Ford Elite and Mercury Cougar are quite similar as well as are the 1977 to 1979 Ford LTD II, Mercury Cougar, and Ford Thunderbird. In short, although your particular model is rare, it has a large extended family and parts are still plentiful.