Checking them for length a good idea too, especially if they have been used a few times. There might be an odd one that has stretched. They are out now but marking any that are either stiff or very easy to remove warrants checking those with a bit more care. Wind them all into the block without the head on just in case there are any that don't want to go down that last fraction. This will also help clean the threads. They should wind in smoothly all the way.

There are 2 kinds of head bolts, regular and torque to yield. An engine this vintage won't have torque-to-yield bolts. You can recognize them because the body is somewhat necked down. Torque-to-yield bolts are not supposed to be reused, although I've done it before I knew about this with no problems. I'd use the old bolts if they look okay.
--
1992 745, >500k km

Hello Dave,

I routinely reuse head bolts after I clean and inspect them.

Look for pits and material degradation along the shaft but occasionally a bolt can't be used because it won't hold a torque.

I have NEVER had a used head bolt break while installing or torquing only while disassembling a used engine.

New head bolts are still available.

I have plenty of good used ones too.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com