I had everything off the front of the engine to check the timing chain, I put everything back together started her and she was running good, but when I turned the key off the altenator sstarted constantly pouring smoke until I disconnected the batt. Whys it doing this?

 

Sounds like something inside the alt. shorted out.

 

more then likely the nut for the main cable is not tight enough and and over heating the post from too much resistance or when you took off or installed the nut you twisted the post and damaged the contact inside. Or you may have over tightened the drive belt and destroyed the front bearing.
what was the reason for the engine stalling in the first place or have you not figured that out yet?