Would an engine from a manual shift 1991 dodge shadow work in automatic shadow?

No, a manual transmission engine from a 1991 Dodge Shadow will not directly work in an automatic transmission Shadow without significant modifications. The primary reason is the different bell housings. The bell housing is the part of the engine that bolts to the transmission. Manual and automatic transmissions have different bell housing bolt patterns and configurations. Even if you could somehow adapt the bell housing, you'd also need to deal with the different clutch and flywheel setups (present in the manual, absent in the automatic). In short, it's a much more extensive project than simply swapping engines.