340 Oil leak?

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70net440

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Anyone had a problem sealing the front and /or rear of the intake manifold? The machinist said the cork gaskets were too thick and the bolt holes wouldn't line up with the heads. We've tried silicone twice and still have a leak. I noticed there are oil holes on each end of the valley rails were the manifold mates up. Do these need to be plugged?
 
Those arent oil hole. From th factory there is alittle peg that goes in the hole amd sits in the intake to keep it aligned.

Ive used silacone with no problems. Go to the parts store and get a tube of The right stuff silacone. Its the best around.
 
fastbackcuda said:
Those arent oil hole. From th factory there is alittle peg that goes in the hole amd sits in the intake to keep it aligned.

Ive used silacone with no problems. Go to the parts store and get a tube of The right stuff silacone. Its the best around.
Click to expand...

I agree with Adam. That's the one thing that went RIGHT with my recent rebuild. Lay on a thick bead and let it set up for a few minutes until it feels like a piece of fudge. Then assemble.

And remember...your not decorating a cake. Lay on enough to fill the gap with some excess.

BTW: If the leak is predominate in the back check your oil pressure sending unit too. :thumrigh:
 
and make sure your pcv system is functioning right, and there is not excessive blow by. Also, to use silicone efectively, there can be NO grease or oil, incluing from your fingers on the surfaces...wipe them down with a clean rag and brake clean or laquer thinner, then dont touch them..
 
Thanks for the replies guys. If it warms up a little bit this weekend I'll give it another try.
 
Hey Fastback, I just noticed the copy of Cartoons in your signature. I loved that mag when I was a kid. :D
 
Do everything they said and here is one more thing. Bend up the head gasket tabs and lay some silicone under them and the bend them back down. Then lay a 3/8 thick bead. Let it dry and trim. If it doesn't sqush out then you didn't use enough and start over.
 
I'd take a razor blade and cut the head gasket tab off. Do the bolts go in easy? The silicone has always worked for me.
 
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