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...I believe they were Hex Heads.

You can't deliver much torque with a 'Allen' Head tool. In My View. They work but have a Smaller 'Contact' Area.

The Smart choice is A 12 Point Bolt Head, gives you more Angles to wrench on, around the Tubes. If the Box End Wrench is Too Close to the Header tube for clearance, Grind it Thinner. I found there is No room for a Rachet Handle and Socket! Of course, with a Hex Head you can use a Open end wrench, but it will try to Slip!

Depends on YOUR Header Tubes.

Last edited by marlinjack

The "original" header bolts were unique to the Pantera. They are similar to what you can buy today from sources like Mr.Gasket as header bolts.

They are hardened hex head 3/8"-16 NC threaded bolts BUT the heads were unique in that they were not 3/8" hex heads, they were m10 metric.

They don't match up length wise to what is currently available either such as 3/4" long or 1" long. I can't tell you the exact length since I no longer have any here, but they may have been metric in length as well?  23mm seems to come to mind but I may be incorrect on that?

More then a few early owners were stumped when trying to remove their original DT supplied headers when the sockets would spin on the heads of the bolts.

I don't know of any current sources of that combination now.

Last edited by panteradoug

These aren't the stock bolts (of which I think I have a couple sets - PM me if you are interested...  Also have NOS original headers in Ford Boxes).  but...  Here's an article I wrote for POCA newsletter...



Anti-Loosening Header Bolt Modification:

An easy way to keep your header attachment bolts from loosening up is to chuck them up on your lathe, and to machine the bolt heads so as to form an insert that fits into the header bolt hole but retains the flange on the bolt for seating.

Take your 3/8"-16 x 3/4" header bolt, and machine the lower half of the flange down from .550” to .430”.  This reduced diameter will slip securely inside your header exhaust mounting hole.

The combination of the installed friction on the head, and additional friction on the newly reduced diameter head inside the header mount hole keeps the bolts snug.  See the pictures below.

351C Header BoltsHeader Bolt 01Header Bolt 02IMG_7475Uploaded 01-20-2018 [21)

Attachments

Images (5)
  • 351C Header Bolts
  • Header Bolt 01
  • Header Bolt 02
  • IMG_7475
  • Uploaded 01-20-2018 (21)

...THAT Is a Fantastic Idea!! Plus the Bolt, going Deeper, Contacts Another 1-2 Threads! AND, Guarantees the Header Flange will NOT 'Walk' around the smaller diameter of the Bolts*, which can cause the Bolts to loosen in the First Place!

Well Done Rocky! I'm going to do that the nest time I Pull the Headers.

Thank You

* as in 'Hot and Cold' Cycling.

MJ

Last edited by marlinjack

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