So if you find one before that and it has low mileage it's a keeper. In 93 Ford dropped the forged pistons in all the 5.0 HOs. The Tbird cam went on to be the cam used in the 93 - 95 5.0 Cobra while the standard 5.0 Mustangs got the same HO cam that was always in the Mustang 5.0 HO. This same engine in 94 - 95 went into the Mustang with exception of the cam and factory headers. The biggest fail on this platform was the exhaust, weight and AOD transmission backed by 3.08 gears. A new cam shaft was developed to get more torque out of the engine after they found that the exhaust system had to be compromised to fit properly. The upper intake manifold was shortened for hood clearance. For the 5.0 all the front drive accessories had to be close up against the front of the engine, a shorter water pump was designed and shorter stock shorty headers. So because of the smaller engine compartment the 5.0 and then later 4.6 had to be squeezed into the small space. Ford thought it could survive on the V6 and soon found it couldn't. The difference being that the MN12 was never designed for a V8 from the start. Then this 5.0 was slightly different than the standard HOs that were in the Mustangs up to 93. Ford did not bring back the 5.0 in that platform until 91. If this is an MN12 platformed Tbird than it is 91 - 93 and not an 89.

88 tbird