yes the transmission will still operate correctly
You failed to mention what fluid you accidentally put in. In any case, have the transmission fluid flushed out and replaced with the proper ATF right away.
Have it cleaned out and flushed immediately
You should drain the oil in the engine. Put engine oil back in the engine because the transmission oil is not made for engines and will hurt the moving parts of the engine if left in.
Then you may or may not have ruined it. It is, however, your fault.
You need to get the trans fluid changed immediatley
Do you mean into the engine? If so it depends on how little; a quart is too much for a small engine. There wouldn't be any immediate damage but change the oil before running the car again.
to the transmission, not the engine
You should never add transmission fluid to a Chevrolet 350 engine. You can add transmission fluid to the transmission through the transmission dipstick holder.
NO!!!! do not do this, oil is oil, transmission fluid is transmission fluid, and antifreeze is antifreeze, do not mix any of these, it can perminately damage your engine.
go on bing.com
If you mean "in" the engine, as in "instead of motor oil," the answer's no. I guess you could probably put it on the engine, if you can explain why you'd want to.