There's an old shade tree method for torquing bolts you don't have an exact spec for that's worked well for me for a lot of years. "Snug plus 1/6 turn". Take out all the noticeable slack between the parts you're assembling, and then turn the hex bolt head one more flat. That stretches the bolt slightly and keeps it tight. It's surprising how closely that method matches the published torque specs on things like head bolts, main bearings, and similar components.
Jerry
