A .060 overbore will clean up most deep pits.
By boring .060 overbore you can use replacement
pistons (cast ones) that have a double valve relief configuration for either 389 heads or 400 pontiac heads. If you decide to upgrade to 400
type heads the standard bore 2262 TRW/ Sealed
power/ Federal Mogal pistons are the ones to use.
I have a new set of either pistons if you cannot
find them elsewhere. The pistons and the crank will need to be rebalanced for the 400 piston weight. Good luck. Tom V.
ps My 389 GTO engine is .060 overbore.