There are many electronic tuners out there that can plug into the diagnostic connector for your car and override the pre-programmed settings. (Google "Diablo Predator" for one of them) Some will even be able to compensate for the extra speed.
However, your vehicle being a 1995, you may have "OBD1", the older type of system, and it may be pretty hard to find something that will increase performance for this.
That and I have no idea why you'd want to go over 100 in something that handles and brakes like a Silverado. (or most big trucks)