Looking for feedback on the correct small block distributor hold down bracket for 1970 A-Body with a 340 engine assembly. I've seen two styles... One bracket is a W-shape (small fork in the center) and the other is a U-shape.

My one owner '69 A-body 340 clamp is the same as the bottom photo.

The surface finish on my clamp is blackened copper plating - no paint. The blackening is done with sulfur (liver of sulfur), according to Google. If you carefully clean the part you may find a black finish.

I've seen other posts that said the clamp was copper plated with copper color, not blackened. I'm guessing they found the copper plate but failed to discover that it was blackened copper plate. Minor abrasion during cleaning will destroy the blackening.

In your photo, the lower edge without paint looks like it might be blackened copper with small areas of copper color showing.

The bottom part is correct and you can see the copper showing through in a few places. It is not "blackened" but is conventional electrolytic copper plate.

- EM

Never seen the W style before, might be really early. Not sure why they copper plated these but they all were. Maybe it was to help ground the distributor to the engine block?

the w style is for the magnum engines that the timing is computer controlled,the dist shaft has a recess in it that the w fits into,so you cant adjust the timing by moving the dist

Never seen the W style before, might be really early. Not sure why they copper plated these but they all were. Maybe it was to help ground the distributor to the engine block?

Bingo!

These are NOS 1947 612 clamps for sale on eBay. 1947 612 is from the early 1960s. My 1969 clamp is 1947 613.

If these in the first 2 photos are copper plated, then they were blackened.

The bottom 2 photos are from my 1969 340. The copper plating is still partly black. As mentioned above, cleaning the part removed much of the blackening. Or maybe the blackening degrades with time and exposure to the engine bay environment.