Originally Posted by Anonymous
why not 1993?
I think quick5pnt0 said "1989-1992" because 1993 Mustangs had cast hypereutectic pistons in it's engine while the years before had forged pistons. Hypereutectic pistons are great for few reasons such as tolerances can be set closer, they are lighter, and cheaper. Problems with them is that they are weaker than forged pistons and don't hold up well to the stress of nitrous or supercharging.