[Kenth]

Again, the 1967 (and the revised 1966) rod is stamped 6 qts.
This is for the amount of oil in the tray, add to that whatever goes into the filter used.
All other rods is stamped 5 qts for the amount of oil in the tray.
Obviously the rod cannot measure the oil in the filter used.

(I would love to see a Pontiac V8 rods stamped 7 qts from factory)

The short filter was introduced for 1967 Pontiac V8.
Long filter for 1966 and earlier.

FWIW