Cylinder head stud what thread ?

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May 20, 2004
Can anyone tell me wht the thread type and size for the front cylinder head studs on a 76 mk 3 850 are? They are the two which have the nuts underneath on the barrel, which are alomost hidden.

Another maybe dum question how do you torque them up, there is no way to get a socket in there ?
3/8" BSF

They would be 3/8" BSF, if they are the same as the RH4 850 & 2 750 heads I have in my possession.
That is the thread in the head, the other end would be cycle(26tpi), unless they changed on the Mk3.

I have a ground down 1/4" whitworth socket to fit down the head holes to tighten the nuts up. The socket doesn't have the lip on it anymore.
Same for the Bolt near them.

You also need a ground down socket for the bolts under the fork legs.

Actually, Dynodave has a good section on norton heads:

Hope this is of help to you.
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