383 build
Unless you actually KNOW how the bottom end is..... Your taking a chance.
You could roll the dice. If it starts to rattle after a while, you can rebuild it then. Or rebuild it now.
If you take it apart, the condition of the bearings and crank need to be OK. I would not exspect perfect.
Your cam choice will be limited to valve lift with the Pistons not having valve reliefs.