The ACC40 (introduced in 1970/71) also used the G153 until 1973/4. The ACC 40 series had a basically rectangular look and rectangle shaped tube OHG with no bolt on side counterweights, sectional valve & hydro static power steering. The F40 had what was referred to as a water fall shaped counterweight with bolt on external side weights, round tube OHG members (basically it was "Butt Ugly") and hydraulically assisted drag link steering and mono body hydraulic control valve. I was the Product Marketing Guy over this design change (I had nothing to do with the change to the F163 but it was done for economic reasons).