Will a 1996 1.9 Saturn engine fit 1999 dual overhead cam Saturn?
No, a 1996 1.9L Saturn engine (likely a single overhead cam, SOHC) will almost certainly not fit a 1999 Saturn with a dual overhead cam (DOHC) engine. The engine blocks, heads, and associated components are significantly different. Even if you could somehow physically bolt it in (highly unlikely), the wiring harnesses, computer systems, and other crucial components would be completely incompatible.