the 94 GP will get 160 hp to the wheels and not at the fly wheel. I had my 93 dynoed at my college and it got 156hp and 183 foot pounds of torque at the wheels it has the older 3.1L V6 in it. Its rated at 140hp and 184 foot pounds. it is bone stock and it has almost 160,000 miles on it.
the 3.4L four cam is rated at 222hp and 238 foot pounds
turbo 3.1L 205 hp and 225 foot pounds, quad four has 180hp 160 foot pounds.
your car is known as a W body car so the 3.4L and turbo 3.1L where made only for that frame other cars that are the same as yours are the Chevy lumina the olds cutlass and Buick regal. The way that you can tell is through the Vin number. just thought you should know.