For the 292 engines, the majority of my Y builds use the Best Gasket neoprene seals that come in their full gasket sets. In those instances where I’m not doing a complete rebuild or simply need an individually packaged neoprene seal for a 272/292 Y engine, then I’ll use the Fel-Pro seal BS6141. Be sure to examine the seals very closely as any voids or pin holes in the seal material that happens during their manufacture will cause an early leak or failure. Here’s a picture of a new seal that was defective out of the box.

I’ll say No. They both look the same and I’ve had the same good results with each. The Fel-Pro seal is simply easier to buy by itself on my end when I don’t need a full set of gaskets.

While I haven’t needed to forfeit the use of the rubber side seals and nails on either the Y or FE engines, I don’t see a problem with using RTV in the slots assuming that both of the slots can be successfully filled with the sealant. The key here is getting the RTV to the far end of the slots to insure there is not a void there in which oil can pass through to the back of the engine. I do put a small amount of RTV in each hole before starting the rubber seals in place and this RTV essentially helps to thoroughly seal the far end of the slot when the rubber seals are completely pushed in place.

Mark. On high mileage Y engines, it does appear to be the rear main seal itself being the main culprit in regards to oil leaks. The other items on a high mileage engine contributing to those rear leaks to a lesser degree still includes the oil pan gasket, valve cover gaskets, valley cover gasket, and the oil pump. On fresh rebuilds, the side seals appear to be more of an issue and part of that is simply installer error. Installing one half of the seal or even both halves in backwards also seems to be happen more often than it should. And on the fresh rebuilds, oil pump leakage is also mistaken for rear seal leaks as well as oil pan gasket or oil pan bolt leakage in the rear seal retainer area. Side seals is still the source of the highest incidents of rear leakage though where the rear seals are being worked on. FE engines have essentially the same problems in the rear seal area as the Y engines when it comes to seal installation issues.

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Offsetting the neoprene seal halves just hasn’t been brought up recently on this site simply due to the much referenced detailed instructions that can be found at the following link.

http://www.eatonbalancing.com/blog/2008/09/10/neoprene-rear-seal-installation-for-the-y-and-others/

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Here’s a link to a past thread commenting on the ‘why’ for offsetting the neoprene seal halves.

http://forums.y-blocksforever.com/FindPost69998.aspx