2002 Subaru Legacy L 2.5

I need to replace the motor on a Subaru Legacy L 2.5 liter .Could some one please tell me the difference between Manual Trans engine and Auto Trans engine. I can get a used block no heads engine from a Auto Trans engine for $450.00 my vehicle is a Manual trans engine. What are the differences besides the bell housing of the engine.

Thanks for your help.

I wouldn't think there would be anything really, unless the crank itself is made for a flywheel or a flexplate.