Volvo Repair: head gasket, timing gears, head gasket

Question
I have a 1995 Volvo 850 non-turbo. The camshafts dont have timing marks on them. I have the head out and ready to go but cant put it back on because no timing marks. It is a 5 cylinder so no copanion cylinder to observe valve overlap.  PLEASE HELP thank you.

Answer
THERE ARE MARKS ON THE TIMING CAMSHAFT TIMING GEARS.THERE SHOULD BE A SMALL SCRIBBED LINE ON EACH ONE ON THE OUTER FACE OF THE GEAR NEAR THE TOOTH PATTERN.THESE 2 MARKS LINE UP WITH THE 2 V NOTCHES ON THE COVER THAT GOES ON TOP OF THE HEAD ABOVE THE 2 GEARS.THERE IS ACTUALLY A SPECIAL TOOL THAT LOCKS BOTH CAMS IN PLACE TO THE TOP COVER SO THE CAMS AND COVER ARE PUT ON AS ONE UNIT WITH THE CAMS IN TIME.