what motor to drop in?

[roadking]

i have 71 6 banger starting to smoke alittle, thinking about getting a valve job done but i have chance to buy a used v8 motor and tranny out of a 82 pu, ( tow lot left over)have not figured ouy what block it is yet but runs well and does not smoke( going to do a compression cheak today) questions are will this be a bolt right motor and when did all the computer crap start effecting chevy motors. oh yea 500.00 for motor and tranny