Only one year ago, Ford Motor Company offered three lines of intermediate and full-sized cars with conventional three-box layouts and rear-wheeldrive: Fairmont/Zephyr, Granada/Mon-arch, and LTD/Marquis, along with its intermediate specialty family, represented by Thunderbird/Cougar. For 1983, there are substantial changes in that model lineup. The Granada and Monarch lines will disappear forever. Fairmont and Zephyr will change at midyear into new, smaller frontdrive cars, the Ford Tempo and Mercury Topaz. Thunderbird and Cougar are completely restyled, and the LTD/Marquis line becomes LTD Crown Victoria and Mercury Grand Marquis. In place of the disappeared Granada and Monarch lines, Ford has engineered new cars, using the LTD and Marquis nameplates for the new family. Both are 5-passenger, rear-drive cars, available in 4-door sedan and station wagon models only. There are no coupes.…