I have used the non-OEM billet seal retainer for the 312.  No idea what brand or where it came from as the customer supplied it. No leaks and it fit as it should. For the 292 engines, I have a surplus of used ones so no need to outsource new retainers for the non-312 blocks.

Lorena, Texas (South of Waco)

I would go for the billet one because it seems like it would be more robust and has brand new threads for the studs and less chance of stripping.

Have you used these for 312 and 292, Ted?  I remember some being on eBay a few years ago but there was apparently some problem with them.  The seal groove did not align or something like that.  They may have been produced by someone else entirely.


Lawrenceville, GA

Thanks Ted,
I grimaced and bought the eBay one.

man they dont know what to ask.i sold my last one for 20.

Depending upon your budget, new billet rear seal retainers for the 312 engines are available from Larry’s Thunderbirds.  Here’s a link.
T 6335B Rear Main Seal Retainer 312 For 1955-1956-1957 Ford Thunderbird (T6335B) - Larry's Thunderbird & Mustang Parts (larrystbird.com)

Looking on EBAY can also find some used rear main seal retainers.  Here’s another link.
Ford Mercury 312 Y Block Rear Main Seal Retainer With Bolts for sale online | eBay

Lorena, Texas (South of Waco)

Looking for a real good rear main seal carrier. Good threads, clean seal groove.