the 95 grand prix did not come with the 3.8 liter engine.The engine should fit fine,unless the grand prix is a GTP model, which comes with the 3.4DOHC.Otherwise, the grand prix is going to be the 3100 engine,just like the one in the grand am and it should be allright. There will be a some modifications to be maqde to the vehicle and the engine to make it fit, because there are always going to be little differences. However,without doing the labour yourself, an engine swap is generally very costly. One point worth making, is that the 3100 engine is not the most durable GM engine,and depending on what kind of miles it has on it, it may be near the end of it's life already. I would recomend having your gaskets changed while the engine is out of the car, becasuse GM factory gaskets are terrible, and made of plastic and rubber etc. They sell aftermarket aluminum or other metallic based gaskets that are much stonger. The 3100 is infamous for itake manifold gaskets and head gasket failures.
