coarse & fine threads on headbolts?

[AnthonyG]

I've got my 8ba right head & engine bank cleaned & prep'd ready to install. I see barners speaking of coarse and fine thread prep on the head bolts. Of the 24 bolts 10 r short and 14 r long but all of the ones i removed seem to have 7/16" X 14 threads? What am i missing?

[JSeery]

That is confusion between head studs and head bolts. Both 59a & 8ba blocks are taped course threads. The studs are course threads into the block and fine threads on the end of the stud that the nuts attach to. Bolts would have to be the same thread as the block, the course threads. And all the head bolts are the same thread size.

[V8COOPMAN]

And DO NOT run a tap in the threads in the block for the head bolt holes. You can run a thread CHASER if necessary. Henry threaded those holes a little tighter than standard to help with water sealing and to preclude bolt/stud wobble. DD

[AnthonyG]

Beings I started this thread ill use it, what's the preferred head gasket to use for the 8ba with Offy aluminum finned heads? Mfgr and PN# would be great.

[AnthonyG]

bore looks to b 3 5/16"

[40cpe]

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I don't know if it is "preferred", but I used Best Gasket big bore head gasket sprayed with Copper Coat. I used Permatex #2 on the bolt threads. Maybe overkill, but I have no leakage problems

[frnkeore]

Originally Posted by V8COOPMAN

Henry threaded those holes a little tighter than standard to help with water sealing and to preclude bolt/stud wobble. DD

That is true, actually, a lot tighter. Here is Henry's thread spec. The normal drill size for 7/16 x 14 is .368, or a "U" drill.