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I was checking out the header bolts that came with the headers from Hall and noticed a size difference between those and the bolts I took out even though the header flange seems to be the same size. The bolts I removed were 1.25 inches in length and the ones with the headers were 1 inch. Does it matter if the new bolts are shorter?

On another note, I was looking at the gaskets that came with the headers and they don't have the slotted bolt hole so you can slide them in. Anyone have a favorite exhaust gasket (not that these wouldn't do but figured maybe they are cheapies).
Just wanted to bump this question to see if anyone had any insights:

quote:
I was checking out the header bolts that came with the headers from Hall and noticed a size difference between those and the bolts I took out even though the header flange seems to be the same size. The bolts I removed were 1.25 inches in length and the ones with the headers were 1 inch. Does it matter if the new bolts are shorter?
quote:
The bolts I removed were 1.25 inches in length and the ones with the headers were 1 inch. Does it matter if the new bolts are shorter?

Yes, it matters.

In general, you want a bolt's threads to engage at least twice the bolt's diameter. Depending on the header flange thickness, I would think 1" might not meet that minimum.

Larry
Last edited by lf-tp2511
quote:
Originally posted by Tom@Seal Beach:
Khan, did the longer bolts by any chance bottom out in the head??? Possibly that is part of the reason they didn't want to come out? Depends on how thick the flange and gasket are, but 1.25 seems a bit long? I think Larry's rule of thumb sounds good.


I just measured the depth of my stock Cleveland heads that's sitting in a box. It's 1 and 3/16th to the bottom of the hole. It's the same with my Edelbock heads. It's a good idea to check the actual depth of the bolt hole for the head. You also have to consider the thickness of the header flange and the washers you are using. The flange thickness on my MindTrain headers alone are 3/8th inch.
quote:
Originally posted by Tom@Seal Beach:
Khan, did the longer bolts by any chance bottom out in the head??? Possibly that is part of the reason they didn't want to come out? Depends on how thick the flange and gasket are, but 1.25 seems a bit long? I think Larry's rule of thumb sounds good.

The bolts didn't appear to be bottomed out and I am pretty sure that the headers had never been removed since the car was built. I'll measure the holes regardless and follow the advice here.

Thank you gentlemen!
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