I didn't notice much difference between my 73 and my 69, but I don't
think "ponderous" is exactly the word. When I get the swaybars on it
it should be more nimble but with an IPD street perf cam, a B30E head
and a fairly decent porting job, even with SU carbs it'll snap your
neck with a 3.31 rear end. Overdrive is a little iffy until you get
over about 70 or are going downhill (traveling east in Kansas is downhill
enough - it drops more than 3000 feet in the length of the state!)

The only thing that makes a 164 less "nimble" than the 140s is that the
engine is somewhat heavier, but at least to me, the power more than
compensates for that.
--
George Downs Bartlesville, Oklahoma