454 Head Bolt Markings

[Sheldon S.]

I am trying to figure out what is correct head markings on the head bolts for a 1971 454. I know they should have an X with I think either a small m or o in the corner of the X. Is this correct or should it be something else.
Thanks in advance.
Sheldon

[Joe L.]

Re: 454 Head Bolt Markings

Sheldon-----

I would decribe it as a "cross" (+) rather than an "x". On original bolts, the ends of the cross extend all the way or nearly all the way to the raised perimeter of the bolt head. There may or may not be a manufacturer's ID seen in one corner of the "cross".

More recent SERVICE bolts have a smaller "cross" with ends falling well short of the perimeter of the bolt head. They're 100% functional, though.

[Sheldon S.]

Re: 454 Head Bolt Markings

Joe,

The bolts I have have both a m on some of them and an o on the rest. So I take it the m and o are two different manufacturers and both are acceptable for judging.
Sheldon