I used to run blockhugger headers on a SBC. Kept having gasket problems. Ended up cutting the flange between the pipes hoping the headers would fit better (I assumed they were warped, cutting the flange would allow the pipes to easily be pulled straight when the bolts were tightened, or so I thought) ... this didn't solve my gasket problems. Turns out the gaskets I was buying had exhaust port holes that were too large for the headers I was using, leaving very little of the gasket to actually contact the head and make a seal. Ended up buying a gasket set that had smaller exhaust holes and never burned through a set again.

The guy I bought the headers from also had this problem and he even tried the copper gaskets with no success.

Sorry, I do not have any part numbers (or even the manufacturers name) since this happened several years ago. I have since returned to running factory cast iron exhaust manifolds due to the emission clampdown. I know headers can be legal, I just wanted my engine to appear as stock as possible (this included sandblasting the aluminum valve covers and intake manifold and painting them the same colour as the engine).

I just use the steel shim gaskets for sealing stock manifolds....I think the trick is to retighten them a few times, like retorquing heads or wheels. Its when they get loose and the gasket blows out.

flatblack55delivery

Like poncho I use the stock steel and fiber manifold gaskets. For the collector flanges the best thing I have found is anealed aluminum cut to fit.

Sorry Fatstax I guess I shuda read the instructions .What am I going to do with the extra peices now. Ed

Hey Ed;
I've always had issues with those darn gaskets. I just bought a set of Remflex gaskets, and they seem to be leaps and bounds better that the old crap I've been using.
These are made from graphite, and are a full 1/8 thick. they are supposed to crush down to 1/16 and are designed for warped headders or corroded exhaust manifolds.
I actually put them on just before the Port Perry show last weekend, and they seem fine so far.
Dan

http://catalog.remflex.com/

 

BTW; Those Fatstax "custom built dual layer header flanges" looked friggin sweet !!

-- Edited by hemi43 on Monday 2nd of July 2012 08:02:58 PM

-- Edited by hemi43 on Monday 2nd of July 2012 08:07:00 PM

-- Edited by hemi43 on Monday 2nd of July 2012 08:07:51 PM

I have always used the High Performance Hi Temp Silicone. Just lay a thick bead and let it cure bolt the headers on and you are good to go. The secret is to let it come to a full cure first.

Throw the headers away and run a set of ram horn manifolds, never eversaw a set of headers that would honestly stay sealed indefinitely....

I've used fel pro and have had good luck with them but I also coat them with high heat gasket maker on both sides and let them cure for a couple hours,they will last longer but you do have to stay on top of the bolts,you can crank them down tight and go back a week later and don't be surprised to find a couple loosening already.