# 67 GTO rear main oil seal use viton or best gasket



## fiesta62 (Jan 12, 2011)

hi, just bought my first gto after 1 year search, a 67 gto ho auto, it has a leaking rear main, just wondering which seal to use i wont be doing the work but i want to make sure i give my mechanic the correct part...i read about viton and best gasket or open to advise anyone ? thanks


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## Eric Animal (Oct 28, 2007)

VITON rear main seal. Can't recommend a gasket today, but will find out for you and post...:cheers Eric


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## fiesta62 (Jan 12, 2011)

eric...i'm no mechanic but i understand there are 2 popular rear main seals used, the viton or the one made by the company called " best gasket company " they make a graph tite square rope seal, apparently very good, i was just asking which one was really the best or if there were other options, i have read more on this and seems the best gasket brand may be the way to go....but still researching...thanks


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## tags68 (Oct 6, 2010)

Yeah , those are the 2 ive heard good things about .. I think there is an issue with the Vitron if you have had crank work done, but i dont know much about that..

The other thing to double check is make sure it is the rear seal. I thought i had a rear main seal leak in my 64 and my 68 .. in both cases it was the oil pan gasket (64 was a bad install, and the 68 was 40 years old)


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## geeteeohguy (Feb 2, 2008)

OK, here's my take. I did a bunch of research on both seals, and installed a Viton BOP seal in a 389 for a friend about 3 years/6000 miles ago. No leaks, dry as a bone. I installed a Viton BOP seal in my 400 back around March of this year, after driving the car over 25 years with a puking rear main. This engine never sealed well, even after I rebuilt it in '88. I've gone about 3000 miles so far, and it's leak free and dry as a bone. First time ever. No oil drips in the driveway after it sits for an hour after a 170 mile drive on a 95 degree day. That's sealed. The big main blocks (421-428-455) had some issues with the Viton seal early on, but that's been addressed. Some crankshafts have a rough area where the seal rides, and in this case, a lip seal won't work as well. The 389's and 400's have a cross hatching for the rope type seal, but the lip does not contact it...so it works. I have heard nothing but good results from the square-cut Graph-tite rope seals, as well. I think it's a toss up. I bought my Viton seal before I knew of the Graphtite ones....I think you'll be fine with either one. The Viton takes care when installing, and the instructions MUST be followed to a "T".


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## DaleGolds (Oct 25, 2010)

I have been doing a lot of research on this subject as well. I have a 65 GTO with a 69 428 in it with a leaking rear main. Actually the word leaking does not do it justice. I have found the same thing that it is a tossup between the BOP Viton and the Best Gasket Graphite seals. I have also read the same stuff on the 421, 428, 455 engines that the Viton does not work as well. Some say it is a bore problem while others say the original crank is too rough where the Viton seal touches. I am going to pay close attention to these two areas before I make a final decision. As of now I am tending to lean to the Graphite seal because it has had better results with the bigger engines. A lot of the professional rebuilders prefer the graphite seal made by Best Gaskets. I too am concerned about the longevity of the seal because the car sits a lot during the winter months.

Dale


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## GTO JUDGE (May 14, 2005)

I had this Vitron seal installed spring of 2010. Bone dry. Color is a deep dark tan color. Hard neoprene not graphite.


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## jetstang (Nov 5, 2008)

I used the best gasket, and there is a sticky on the install. I thought it was leaking, but found my speedo gear O ring was leaking, but dumping brown oil, as that tranny fluid doesn't move around, so it's just old tranny fluid. Best Graph FTW. Harder to install, I had to drop the crank out of the way, but I had the motor out.


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## NEEDLEZ (Oct 21, 2009)

Where exactly do you buy it? I am looking on their site and it's like they are just the genesis for the product but don't sell actually sell it?


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## fiesta62 (Jan 12, 2011)

NEEDLEZ said:


> Where exactly do you buy it? I am looking on their site and it's like they are just the genesis for the product but don't sell actually sell it?


i could not find the graptite seal ad on the best gasket site either....i emailed the company twice...yes twice but no reply...bugger them i went and bought the viton from ames. figure from what everyone is saying both work, but overall more guys seem to have used the viton...i was going to buy both and decide but best gasket dont seem to want to sell me one....


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## MaL (Jun 12, 2008)

Got the Viton and have run the engine for three hours on jack stands. Dry as can be so far!


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## DaleGolds (Oct 25, 2010)

NEEDLEZ said:


> Where exactly do you buy it? I am looking on their site and it's like they are just the genesis for the product but don't sell actually sell it?


The BOP website sells both the Viton and the Best Gasket Graphite Seal. Here is the link.

BOP Engineering Pontiac Replacement Parts

Hope this helps,
Dale


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## fiesta62 (Jan 12, 2011)

DaleGolds said:


> The BOP website sells both the Viton and the Best Gasket Graphite Seal. Here is the link.
> 
> BOP Engineering Pontiac Replacement Parts
> 
> ...


cool thanks for that bop site....tony


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