Preferred header gasket

[SoupMan]

Guys,

Just about to install the catalytic converters so I figured I'd replace the header gasket. What do you guys prefer for a gasket. The current gasket is the one that came with the hedman headers. They always leaked from day 1. I know SBC guys love the blue fel-pro gasket and the REMFLEX. Any opinions. I'm running 6x-8 D port heads on a 455.

[jonathonar89]

A common issue with headers is uneven gasket face.  It’s usually good to send to a machine shop for milling it off a bit.  This is more effective than any gasket in most cases.

[81Blackbird]

https://catalog.remflex.com/

I haven't had any problems since I used these.

[Formula8]

I wasn't aware of the Remflex.  I haven't had any problems but next time my headers are off I will give them a try.  I got replacement Doug's header gaskets from Summit and they work very well.  As Jon pointed out, most of the problems are going to be with your flange or the gasket shrinking from heat so it makes sense for you if you are having problems to step up to something like the Remflex.

One thing I did notice when I was mocking up my motor was that my headers have very thick flanges and came supplied with 1" long bolts.  The end two bolts on my KRE heads are threaded all the way through to the head bolt.  When I mocked it up without gaskets, the outer head bolts would just bottom on my ARP head bolts.  With the gasket in, there was sufficient room but the issue got me thinking about guys with thinner flanges may actually bottom those bolts out even with a gasket.  I don't know if this is an issue with factory heads but it is worth checking if you are having problems with the outside ports leaking. 

[b_hill_86]

https://catalog.remflex.com/

I haven't had any problems since I used these.

I must have screwed something up or my headers are junk. I’ve used remflex every time I pulled my engine or heads, so 4 times or so and only once did I get them sealed really well. I’m due for a new set now actually and I’m considering cutting my header flange

[81Blackbird]

Are you going to cut between the outer and center ports or are you going to take them to a machine shop for milling as mentioned?
I was going to cut mine between the outer and center ports buy was advised not to.

[b_hill_86]

The thought was to cut between the ports like you said. What kind of info did you get on it?

[81Blackbird]

I was told that the long flange would help keep it from warping.  But it seems it does it anyway in some cases.  I was going to do it to "clean up" the look but decided not to because of that info.  Also, some of the individual flanges may twist just enough to make it a pain to start the header bolts.

[b_hill_86]

Makes sense that those things could be the case. Hard telling I suppose.

[restlessgypsy]

I use Remflex currently with no issues..