The International Cessna 170 Association

Has anyone tried to get any AOA approved for a 54 C-170? Or, Is there any that are already approved for the C-170?

Ron,
Just a cursory study online indicates a lot of debate on the merits of angle of attack indicators. Here's one example. That being said, here's a list - from least to most expensive - of what I've found available on the market. The two cheapest seem to be quasi-AOA indicators as they compare differences in ram air pressure from two ports. If any of these AOA indicators are used as secondary flight instruments they can be installed with just a logbook entry; no 337 form required. (The Lift Reserve Indicator website says a 337 is required - maybe they haven't received the necessary FAA approval).
$389 Lift Monitor
$450 Lift Reserve Indicator
$625 CYA 100
$1450 Garmin GI-260
$1495 Bendix-King KLR 10
$1675 RiteAngle Integrity
$1995 Alpha Systems AOA
$2101 SafeFlight SCc AOA This is the system Varel installed.

I have the Safe Flight, as noted below. Quite happy with it. Happy to share info if you PM me. I started to install Garmin, but my shop could not fit it on the aircraft structurally and Garmin refunded the $$.

I'd keep an eye on this product, it's currently experimental but soon to be certified. It offers a very nostalgic look, built in AOA indicator along with the other "mundane" guidance we need from time to time !!!

http://www.AeroVonics.com