My gut (luckily not too big & can be changed if wrong) says you should torque the header bolts to prescribed setting when cold, but as I really want to ensure a good seal - am doing a muffler change & took header off to help get off old muffler off it (using obviously new gasket & even new bolts in case 10 year old ones stretched!)

So, are you hot or cold on this question? Like to  hear soon as want to get on with fun (next one - rear brake change!)

Thanks, George  

thanks, radioman - nah, thought if they were tightened hot they'd be wrong - your confirmation confrims it.

George