My '73 GT has a bit of, what I would describe as, timming chain noise. Its a "rattle" at idle and when letting of of the accellerator when in neutral. Is this safe to continue to drive daily (30 or so miles). I'd like to drive it to Carlisle (5+hrs). What harm could be done? Valve/pistion interference? Thanks for any suggestions. Also, what is the fix? New chain? New Tensioner? I've seen somewhere here that a washer can be installed to the tensioner to aid the problem (?).