The Elite Mk2 had the close finning that you see here and under the front housing (not visible here) there is a boss which in some motors had a supplementary air intake through the crankshaft timed as in a front induction engine. Earlier engines used sub piston induction instead but this isn't ideal in a silenced engine for obvious reasons.

Note the change to cheese head slotted rather than Phillips screws for the front housing and backplate

This particular motor has an undrilled boss and the serial number has been edited out of the oblong depression in this picture.