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I'm getting ready to assemble my 289 and wondered what you all thought of rear main seal installation. In the past I have always 'cut' the seal ends flush to the caps, but I have seen an article that recommend an 'offset' or rotated ends so the joint line is actually into the cap/block. This was to prevent leaks

Has anyone succesfully done this?
 

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There are two types of seals. The rope style and the hard rubber. I used the rubber style and offset the ends. A little RTV where the pin was removed from the cap and a little more on the surfaces where the cap meets the block. Hopefully when I re-install the engine and fire it up, it doesn't leak.
 

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I've replaced a number of rubber rear main seals over the years and never had a leak. Offset the seals from the cap split line about 1/2 inch and put a VERY SMALL AMOUNT of RTV around the seal on the cap split line. Be sure the cap and block area are completely free of oil residue. I know I don't have to say this but I will. Make sure you don't install the seal backwards.
 

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Excellent!

Thanks for the scan ::

When looking for a block to rebuild, I always search for a 1980+ block with the better one piece rear main seal. I have good luck with the two piece, but occasionally have a "leaker"..
 

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I've read that the block can be machined to take a one-piece seal, but you have to change the crank to go along with that.
 

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Picture = 1k words.... ::

BTW...FWIW, when I redid my rear main seal, I learned that the black 2-piece seal from Fel-Pro had a tendency to leak no matter if the installation was solid or not. I found that there is also a "brown" 2-piece seal made by Fel-Pro. When I ordered #2901 from Summit the brown seal showed up.

Installed as per the pic above (as I did the black one) and my leak stopped. ;)
 
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