The time has come... 440 freshen for B-body

With 46000 miles I don't think it shouldn't come apart at all. If it were mine, I would regasket it with timing chain and oil pump and a new carb.You said it runs really well. Leave it and work the rest of the car over and keep that budget for the more pressing issues. I would research what heads it has (hardened seats) and finish the rest of the car and enjoy it. I would not get in a hurry to rebuild it, I have been through that several times and wish I had not.