1970 Dart Swinger FINALLY UNDERWAY

I really don't know for sure about the 360-3 its just what I read on here.now even if it is just the 3rd revision of the cast doesn't mean it's not a better cast.When one wares down beyond spec they rebuild it and that cast may have been a better rebuild and they may have used that cast for specific assembly plants that made those vehicals.And that piston scare doesn't line up with the cyclinder scare so that throws a red flag to me that two things went wrong just hard to say what that was.Now that doesn't mean the motor is shot,just get it check and procede forward,you are on the right track anyway it turns out.IMO .010 over would be the worse case senerio and you mentioned your already planning to get new pistons.i know its extra money but it can be fixed if its out of round.BTW you can take your old rings place them in the cyclinder to see if it is out of round just use a piston with no rings to push it down to that spot and look for a gap,a flash light underneth help see around the ring.The thing that worries me is the groove in the motor has no hatch marks in it that I can tell so what ever happened happened after the last rebuild.