Now that I have your attention with that subject line,


What's the Highest Comp ratio that a steel Shim Head Gasket can take? W/O boost or nitrous?


Mike Jeffery Told me on the phone that the Fel pro replacement gasket is good for about 12:1 on motor alone and any higher then we need to o ring and run a copper gasket.


My dart has a steel shim and runs approx. 10- 10.5:1 w/o any problems as of yet with plenty of dragstrip passes and a whole lotta street miles too.



Thanks - this is more of a curiosity than anything.



Greg

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http://www.youtube.com/hyperpack

Don't know the highest, but I have been running the shim gasket with 10-1 and nitrous without problems. The main issue, I see, with the shim gasket is availability. I have a few in stock, but when checking other sources, they are getting pricey.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I run 12:1 and have a victor over the counter composite head gasget....we did Oring the block, but I dont have the Orings in it, because we did it w/ a felpro and the gasket failed...so far so great!!
Andrew

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Wife's: 64 Valiant
My: 70 Road Runner, 67 Barracuda, AND the 62 Valiant drag car!!

Cool Charrlie,

Thanks,

Kidd,

I dont believe you can run a fel pro gasket with o rings - I might be wrong here but I think you can just run copper gaskets with o rings.

Greg

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http://www.youtube.com/hyperpack

Greg
If you dont install the O rings then you should be able to run a FelPro or any other composite gasket.
Frank

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Scrapple: Because a mind is a terrible thing to waste.
73 Duster - Race Car
66 Dart Wagon - DD
178" FED
82 D150
All Slant powered

It is probably possible to get the o-rings to hit the fire ring on the Felpro, but that gasket's ring is not very wide. Tilley in Oz has had good luck using an o-ring on one side of a Permaseal (AU/NZ) gasket up to and a bit above 12:1 comp.

I have run 11:1 comp in my motors with a standard composition gaskets and never had a problem. No o-rings.

Lou

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Home of Slant6-powered fun machines since 1988

for what its worth forty years ago my altered t had 270lbs at cranking speed. it would blow felpro gaskets regularly . thought that i would have to copper o ring it. tried first, set of aftermarket head studs. worked great no more blown gaskets. guessing that motor was over 12:1 its been forty years. got to go to parts for sale.

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restorations and proto types a speciality: if it can be ruint, i can ruint it.