Head bolt torque

[Jordan Princic.]

I've never seen any published. I don't think it's easy to damage by over-tightening, especially if you have an iron head. Handbook says tighten until done up, or words to that effect.
I guess around 20 lb-ft might be about right. If you use a normal-sized spanner and normal hand strength, you should be right. These things were made for soldiers!