Difficult to ID Dampener. '57 with Air?
 

Picked this up in the spring. Does not appear to be a '56 from the photos I have seen. In '58, they went to the more modern style.
It came off a '57 but the car did not have air, maybe a transplant?
The belt grooves are fore & aft with a space between them like a regular air pulley...
Anyone know?

I would say yes.I own single and dual grove like it.That is the first 3 groove I have seen.FYI,that should be sent to Damper Doctor to rebuild it.It has springs and cams in it to dampen harmonics and even NOS ones after this many years wont work properly.The reason they changed styles.Tom

Still scratching my head over this one. It is NOT a 3 groove, that is a space in the middle.
I have heard of Dampener Dr but this one is for resale...

Can you post a pic looking straight into the grooves so I can see the shape of the center?Tom

Note that the inside grove is 1/2 & the outside groove is 3/8.

PS, I see this style of dampener was carried over from the Straight Eights, I would love to see a photo of the guts just to see what is going on in there.
No doubt they were costly to produce as compared to a simple rubber style!

It is a Tri Power pulley :)