engine replacement in 325 bmw

please help! I have a 1987 325e BMW and it is a automatic I blow the engine and I like the so much I thought I would replace the engine. I bought a engine low milage a 1985 325e manual trans. I'm, having a hard time installing it. Is it possible that the 325e manual wont fit in a 325 bmw that was a automatic I'm lost and if anyone can help me plz do so I want to keep my Bmer Thanks