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Old 07-05-2015, 03:31 PM   #1
Zach079xxx
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Exhaust leak

Recently got an exhaust leak, I sound like a 50 caliber getting up to speed. I think its coming from my manifold gasket (I'm hoping). What type of gasket do I need and what brand is suggested? I can't take the pecking anymore. Also I'm going to get the shop to spray them black for the time being until I go another route and get headers. I would do it but I don't wanna break a bolt off and if the shop does its on them.

Here's some pictures.



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Old 07-06-2015, 11:53 AM   #2
albertgen
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Re: Exhaust leak

I have a 78 C10 custom deluxe 305, and there were no gaskets on it. I am in the process of removing the manifolds. The only hard part was I had to cut the 6 studs that attach the y pipe. I am putting on new painted manifolds and heat shields plus new spark plug shields. I had a leak too. I thought I's just go ahead and clean up the engine and make it look a lot cleaner. Al
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Old 07-06-2015, 04:49 PM   #3
Zach079xxx
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Re: Exhaust leak

I've heard some have gaskets and some don't. Maybe it's just me but in the second picture I see a gasket..
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Old 07-06-2015, 08:07 PM   #4
Super_Dave
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Re: Exhaust leak

I had a bad experience with the gaskets supplied by Hedman Hedders; blowouts all over the place. My racing buddy turned me on to Remflex gaskets. Worked great and wouldn't use anything else. http://catalog.remflex.com/
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Old 07-08-2015, 11:59 AM   #5
GRX
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Re: Exhaust leak

Warpage from repeated heat cycles. You can try filling the void with a soft gasket. Proper way would be to have the manifold machined flat. A floor standing belt sander will do.
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Old 07-08-2015, 09:27 PM   #6
raceman6135
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Re: Exhaust leak

No gaskets required.

My 1986 C20 with a 350 engine has the same style exhaust manifold on the passenger's side, that is, the 'log' is above the exhaust ports, next to the valve cover.

When I removed my exhaust manifold to look for the leak, I discovered the manifold itself had a hole in it, hidden under the sheet metal heat stove (which funnels warm air to the bottom of the THERMAC air cleaner).

Not worth it to pay someone to try to weld the cast iron; $20 and a trip to the wrecking yard was the solution.
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Old 07-08-2015, 09:32 PM   #7
Zach079xxx
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Re: Exhaust leak

Ok so I'll just run to the junkyard if that's the case! Thanks
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Old 07-09-2015, 09:33 AM   #8
motornut
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Re: Exhaust leak

I'd look for any manifold cracks/soot,and file mateing surfaces slightly if needed
looks like it had air injection?,check the air injection holes are all plugged,not sure if other spots could blow out but it could sound like that.
i use a spreader if the manifolds don't hand thread in, then leakers get gaskets
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