# Best rear main seal?



## johnv (Mar 5, 2018)

Hi everyone

Novice question alert!

I've read a few older posts about the best rear end seals to use. Seemed the discussion back then involved two favourites:

1. Graph Tite Seal" from the "Best Gasket Co. https://bestgasket.com/vintage-engine-gaskets/

2. The Viton One-Piece Rear Main Seal from BOP Engineering BOP Engineering Pontiac Replacement Parts

Both of these options were fairly new when the discussions I saw were posted, so it was hard to get a feel for the better option of the two.

Is there a clear preference emerged now they have both been in the market for a while?

Any guidance would be much appreciated!


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## bigD (Jul 21, 2016)

The 1-piece seems to be the favorite of most. 

But, some engines REQUIRE the rope, for certain reasons. 

https://www.gtoforum.com/f50/67-gto-rear-main-oil-seal-use-viton-best-gasket-34376/

So, I'd say the 1-piece is the best choice, if it'll work in your particular engine.

http://www.pontiaczone.com/forum/showthread.php?t=30751


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## johnv (Mar 5, 2018)

Excellent, many thanks bigD. Those are great links!

My GTO is a 68 convertible so am hoping the 1 piece is the answer... altho I clearly need to take a good look at the oil pan gasket first!


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## geeteeohguy (Feb 2, 2008)

Have installed several BOP 2-piece and one BOP 1-piece on 389's and 400's. No leaks on any of them after several years and many miles. Not a drop. However, if you have a big-journal 421-428-455 engine, the Best-Gasket square section rope seal seems to be the best choice. Due to crank diameter and main cap design, the Viton BOP seals seem to have issues sealing these engines up.


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