I just ordered headers and I'm reading about the bolts being to short. Are there any particular bolts better than another. FYI I ordered Ford headers & the salesman said the "Stage 8" hardware is no longer avail.!? I was debating on contacting ARP. Any suggestions?

 

No knowing the thickness of the flanges of the Ford Racing headers, take this as info....I have the banks headers on my truck and my headers bolts measure 8mm x 1.25 x 3mm.

Hope this helps.

 

The parts guy couldn't tell me the thickness. I'll just have to wait & see. I actually wanted the Banks but $$$$, Too much difference in price (I may be regretting it later). Anyway, So they ARE metric. I've heard stainless, gr5 steel, gr8 steel, nickel coated, you name it. I guess dissimilar metal corrosion is what I'm getting at. And how deep into the head (I would assume 3/4" at least 5/8")....... Unless I'm misunderstanding your length doesn't seem right.

 

Boxcar
Jumping ahead here, If I assume you meant 30mm in length, minus the hdr flange & gasket That would be about 1/2" grip length? Yes/no/maybe?

 

I thick the Ford headers might have 3/8" flanges. M8x1.25x25mm will do the trick if the flanges are 3/8" thick. Right now I have the grade 5s that came with my Thorleys.

Looks like you can get the 6.8l Stage 8 header bolts yet. Although I think getting the tabs and e clips on is going to be a real *****.
Stage 8 Locking Fasteners 8905 - Stage 8 Locking Header Bolt Kits - Overview - SummitRacing.com

If I get another loose header bolt on my Thorleys I think I'm going to get these. Percy's High Performance - - SummitRacing.com

I have one of the studs that came out of my 04' and it screwed into the head 5/8". I'd say you could get at least 3/4" of bolt in the head without bottoming out.

 

3/8" flange, That sucks!.....I was expecting a little longer bolt since it was going into aluminum instead of steel (But, I guess it would be that much less to drill out down the road LOL!) I looked at the thorleys, But I wasn't crazy about jacking the engine way up in the air (as the install instructions called out), and I thought I had seen where the frame rail had to be trimmed to make them fit?!?.....I aquired an exhaust leak w/broken studs, that's why I'm doing this.

 

Yes I meant 30 mm and they are stainless graded hardware. I installed my kit 5 years ago. The bolt spec is from my parts manual. They are metric.

 

I took out a stud, used the depth gauge on my calipers and found the depth of the hole, added the header flange, gasket thickness, and washer(s) thickness, and subtracted 1/4"