I would not rebuild it , if u find it to be a blown ,head gasket, or cracked head or cyl the cost to rebuild, is more than buying a complete used engine,
if fact in MARCH or APRIL i will be removing my srt6 motor and trans to replace with a 113 SL 55 V8 . This will be my third v8. these engines can take a lot.
to make a long story short i learn about 30 years ago to replace, not rebuild. a factory built engine will last a long time compared to a rebuilt which MAY last 75000 miles . ( that is if you race it like i do) example the srt6 that i got in May of this year with 118,000 miles on it , has gone wide open throttle every time i get in it , mileage now 122.008 and 11 trips down the drag strip. good luck what ever u do