lastcaveman

I`m trying to order a set of header gaskets but need help. Where do I measure the openings on the header. Do I use inside measurements or measure from the outside of the ridge around the opening.?

leadfoot4

Generally speaking, the headers should (roughly) match the port of the cylinder head. I do believe that the gasket makers size their gaskets to the size of the ports on the head.

HeadsU.P.

I assume you are referring to the header flange gasket and not the header collector gasket.
Measure the port on the head. Better to order a pinch too large than too small and have to trim them.

You can get a feel for port sizes by looking at Summit Racing under the gasket category: exhaust> header>flange. You most likely want round shape unless otherwise specified.

cv67

What year, type of cyl head, brand of headers, sure someone can find a pn for you quick.

lastcaveman

OBX header with oval ports to a aluminum head with D ports. I read that as long as the ovals covered the D ports it would work. Am I wrong ?

HeadsU.P.

Sounds right. You could buy gaskets for $20. You can buy gaskets for $40. The difference in sealing characteristics is night & day. If you have the funds I would highly recommend a laminate aluminum set. They will conform to a rough header flange and never blow-out. Percys makes just such a gasket. A little pricey compared to a fiber type gasket but well worth the money.

Measure the heads port and go from there. The header flange will take about any size gasket you offer. I doesn't really care. But correct sizing on the head is essential.

lastcaveman

I have decided to just order another set of headers. I do want to thank everyone for their help. Thank you.

theandies

Get some Earls and you can't go wrong.

naramlee

if your headers don't match 100% that's fine, they just need to be larger than the ports in the heads, obviously you don't want a MASSIVE diff, but 1/8 larger is far better than 1/16 smaller and presents a blockage to outbound exhaust gasses

lastcaveman

That is what I was told. The trouble I`m having is where do I measure to try and match up a set of gaskets. My headers have a raised area around each opening The inside measurements are 1.62 in. X 1.34in. But if I measure the raised area it is 2.18 in. X 1.75 in.

HeadsU.P.

Go with the larger of the two. Doesn't the raised area interfere with a nice flush fit?

naramlee

it wont matter as long as the gasket is larger than the exhaust port but fits a portion of the flange on the header you'll be fine

sure you want a perfect fit, but rarely do you get that

go with the closest gasket to 1.62 x 1.34 but larger