Are you looking for just a block replacement or an engine swap? Your truck is either a Romeo or Windsor engine. The 8th digit on the VIN is what tells you. If its a "6" it is a Windsor. If it is a "W" it is actually a Romeo block. They also have either 6 or 8 bolt flywheels, which may play a part in your engine quest. But if you are looking for just a short block, you should be fine. However, as mentioned above, 99+ pistons are dished, where as the truck, and all 96-98 mustangs have flat top pistons. Your compression will decrease along with TQ.
thanks man for the info. it is just a shortblock swap. it is actually for my friend. he has the truck and wanted to know if he could use my stock shortblock