If you own a 99-01 2 valve Mustang, then your car was plagued with a factory intake manifold that featured a plastic coolant crossover. This factory crossover was prone to cracking at the front molded seam, as well as the temperature sensor and rear heater hose connection would back out from the intake.
To fix the problem, Ford took the exact design and added a cast aluminum crossover in 2002. Thorough changes were made to keep stress off of key mounting areas such as a redesigned alternator mount. So you 99-01 GT owners who could possibly still have the intake manifold with the plastic crossover, you’ll want to grab an upper alternator bracket when switching to the Ford Racing Intake Manifold. This manifold, of course, is a direct replacement for all 2002-2004 2 valve Mustangs since they were already outfitted with the redesigned manifold.
A couple of other things you may want to grab while you’re at it, would be a new thermostat and intake manifold gaskets!