Well the new INA lifters i fitted were exact same size as one's that came out (I presume std size as nothing to say any different) - however didn't get measurement for lifter housings in head. Yes the noise does die away as the car gets warmer, although the 2nd, cam type noise I described remains very faintly. After leaving overnight, lifters have drained completely EVERY morning and tap loudly for approx 2 secs until oil press. has returned to head.

Arrrrgh!