Will an 1988 Beretta engine fit in a 1995 Beretta?

No, a 1988 Beretta engine will likely not fit directly into a 1995 Beretta without significant modifications, if at all. While both are Berettas, the platforms changed considerably between those model years. The engine bays, mounts, and associated components are different enough to create incompatibility. Even if the engine displacement were the same, the specifics of the engine, its peripherals (like the alternator and power steering pump), and the mounting system wouldn't be interchangeable.