Well, LXs came equipped with 5.0Ls, too. For starters you will want the same year wiring harness as the car as there were color changes made in the wiring from '89 to '91 as far as I know. If the car wasn't hacked up then the wiring should just plug right back in there without problems. What are all the specs on the motor? What year block is the 351W? That's important so you choose the correct intake for the deck height. I wouldn't count on that T-5 living very long if you beat on the car a lot. If the motor is really torquey then you'll snap that T-5 like a twig.