Ah! Found it. The 175C model had the CS prop. Thanks for the tip, the
word Powermatic is what I needed...
Wayne


Model R172E/H/J: 210HP, 6 Cyl, 100 Oct Continental IO-360-D**
Model R172K: 195HP, 6 Cyl, 100 Oct Continental
IO-360-K/KB**
Military T-41B & D 210HP, 6 Cyl, 100 Oct Continental
IO-360-D***
Model 175 C & P172D (Powermatic)175HP, 6 Cyl, 80 Oct Continental GO-300-D*

Notes:
* Cessna experienced trouble with the geared engines in the model 175
(also known as the Skylark) and, in 1963, changed the designation
to P172D (also known as the Powermatic) in an attempt to remove the
stigma of the engine. The 175 has always been, basically, a 172 airframe
with some changes. The P172D is even more so: it's a straight 172D
airframe.
For more information, see note 1 below.

Comments:

1. The geared Continental engines used in the C175 Skylark and
P172D Powermatic have a history of upper-end (cylinder) distress ostensibily
caused by the higher RPMs. It is supposedly becoming very difficult
to overhaul these engines as parts are in short supply, especially
for the gearboxes. Major $$$$$ for gearbox parts.

A guy on my field has a constant-speed prop on his GO-300 powered cessna.
It's a Cessna 172 "Powermatic", which is what they called the 175/Skylark
after it got it's bad reputation. The CS prop is from the factory, the
prop
governor is mounted on the back side of the reduction gear housing on top
of the engine.

Any you guessed it, people wouldn't rev the engine high enough, AND they'd
use the prop to decelerate (backdriving the engine), which is a no-no with
a geared engine. So, these engines got a bad reputation.
--
Aaron Coolidge (N9376J)