Idler Pulley ID??
 

Any ideas on these pulleys / brackets?

Any parts numbers on the pulleys? They look cast iron. The pulley without the bracket appears to be identical to the idler on my '66 Caprice, which is also found on the '66 L78 Chevelle/Malibu. None of the brackets are correct for either of the 2 mentioned cars.

3765397 on the middle and right side ones and 3761874 on the left side one.

So yeah, the 3765397 pulleys are used on the '66 cars, maybe '65 as well. I believe that number is for the pulley itself, not including the spindle/mount the pulley is mounted on. The bracket is another sub-assembly. The one all the way to the right and the 2nd from the left have the spindle/mount found on the L72 full size cars and the L78 Chevelle/Malibu. None of the brackets look familiar to me.

My GM parts book says the 3765397 was used on the 63 and 64 409 so I suspect it may have been used with various bracket configurations. I have identified the third from the left as 63 and 64 409.

Appreciate your help Mark.