Barry.  That seal material looks to be the type that was wetted with water before installing in the slots with a RTV type of material.  It then it expanded in place as part of a chemical reaction.

Lorena, Texas (South of Waco)

I bought the Billet Retainer a few years ago.   I ran into the same problem as John described.   The crank opening was not centered. It seems to me they had a great idea, but the machinist could not measure or program the machine properly and made them wrong.  If they would have done them right, I would have tried them.   Another story of taking the time to tool up for a reproduction part and missing a major detail.  I sell stock retainers regularly, so I could see that there would be a need for a quality one.

Pat Fleischman

While we're on seal retainers....has anyone ever seen this type of side seal material? Looks like some sort of  packer??  (From an old 312.)  The 292 retainer...look for the  flywheel bolt impressions in the now cracked back side. Got this engine given to me "It's yours, we can't get it to turn". Salvaged the crank as the block was cracked thru the mating  crank seal area.  Barry L

Just something to watch for on this style of retainer. There appears to be an error in the machining. Check the photos of an old Ford one compared to the new  billet one I've got. Notice the difference between the edge of the retainer to the bolt holes, they're offset on the Ford one and evenly spaced on the billet one. It seems counter-intuitive, but the crank seal area is not centered in the retainer. The new billet pieces seem to ignore this and center the crank seal between the side seals. The difference is more easily seen on the counter-bored side. Hard to really see in the pics, but look for the seal groove shift at the parting line. I believe it was John Mummert that told me about this issue.

I had seen a similar one in the past but no longer available. I don't know if these are the same, it looks good, a little pricey for me.. Says the one for 312 are on back order..

I noticed a new Y-Block Rear Main Seal Kit on Ebay that I have not seen before. Includes new Billett Steel Seal Retainer and either Neoprene or Rope type Seal for all 272, 292, 312 (2 different Kits). Seller claims part of the problem with Rear Main Seal leaks is distortion from age on the original Aluminum Housings. Item #'s are 262081318245 and 261880763668. Never seen this Item before. Any Opinions on is this a legitimate improvement over the original and would help solve the Leaks?