Header Bolts: Thread Engagement

[DRRummel]

I decided to use regular Mr. Gasket header bolts on my DD. When I chased the threads I noticed that the bores we about an inch deep. But all the header bolts I see for sale are ¾ long. Stage 8, ARP, etc for a 302.

Since all the aftermarket bolts were ¾ long and the Mr Gasket bolts are .75 inch long, I went ahead and started to assemble the headers. But this can’t be right. See the last bolt, it is just started in the hole. There only seem to be a few threads of engagement. With a 1 inch deep hole and a ¼ header flange I would think a 1 inch (maybe 1 1/8) long bolt would be better. Am I over thinking this?

Can I pick up a set of 3/8 x 1.00 grade 8 cap screws instead? ARP has stainless steel cap screws, are they harder then the cap screws you can find at the hardware store?

[RUTHLESS]

In the pic it doesnt look like the bolt it threading in straight. Maybe try loosing all the bolts and wiggling the header around and see if you can get it started straight. If its tight dont force it (Well with bolts anyhow).

[DRRummel]

In the pic it doesnt look like the bolt it threading in straight. Maybe try loosing all the bolts and wiggling the header around and see if you can get it started straight. If its tight dont force it (Well with bolts anyhow).

You are right, it doesn't look straight. But it does go in and bottom out. My issue is that it is only goes a few threads before it is all the way in. I would like it if the bolt was at least 3/4 inch - 1 inch into the heads. I would think I am getting only about 1/4 inch bite on the head.

[CobraII]

I'd say grade 8 cap screws would be fine.

It does look like that bolt isn't going in straight. FWIW, I had a problem on my headers this year that I hadn't run into before. The gasket was slighting off, and in trying to bolt the header on, I was hanging up on the gasket. I had to enlarge the holes a little with a file.

[DRRummel]

That bolt would tread in all the way. I have it just hanging there to show how much of the bolt would engage the head.

I just gave in to my 'oddity' and bought 1 inch ARP bolts. I FEEL much better.

Now I just need to find my anti-seize and redo the bolts.