Oversized Header Gaskets

[George Hill]

I've got a car in my shop that has aftermarket headers (I do not know from whom), the issue is the outer (B1) header collector is 56.5mm od and a stock gasket will not work. For reference the inner (B2) uses a stock gasket and is 53.5mm od. You would think the 3mm wouldn't make a difference but it absolutely does and I destroyed a genuine gasket and even an HJS trying to fit them on.

I can't find any reference to an oversize gasket anywhere but surely I can't be the first one to come across this and its a simple I didn't search the correct key word. Can someone help me out here?

[Slideways]

Can you take a picture of the headers from the passenger wheel well? Curious which headers these are as none of the common ones have this problem. My guess is SS reps or something very old.

57mm ID

https://www.walmart.com/ip/ID-57mm-Exhaust-Manifold-Gasket-Prevent-Leak-Noise-Exhaust-Donut-Gasket-Muffler-Ring-Exhaust-Flange-Gasket-for-Car-SUV-Truck-RV-Graphite/16578765482?wmlspartner=wlpa&selectedSellerId=571& selectedOfferId=177844C602803429A175B5C74C0A4CD8&c onditionGroupCode=1

[George Hill]

Yes, they are likely SS reps, ebay specials and are old. I forgot to get pics, next time I have it up I will.

I found this Mahle gasket, pn# ZZL0-40-305 and I've got it installed. It's a smidge loose and the od is a bit large. It is the compressed graphite/foil desing like stock and I think it's going to work.

Also this Fel-Pro 60641, it seems just ever so slightly large than the Mahle, it'll be my back up as it is more of a construction like the HJS gasket than OE.

[ZiMMie]

this will also work.

https://www.rockauto.com/?mfr=WALKER&partnum=31391

i will leave this here for the future. if anyone is also searching.

[x Spades x]

Will cutting the flanges and converting it to clamps be an option? This will be a pain everything the customer needs a new one... and it guarantees a none leak solutuon.

[George Hill]

x Spades x it could be done sure, but for this scenario it would be cheaper and likely better to just buy a different header. Additionally this header flange is contacting the frame rail and I'm not sure there is even room to put a V-band flange on it.