As Cranman says the biggest problem will be removing the manifold without breaking the bolts. When you go to reinstall the manifold DON'T OVERTIGHTEN the bolts. My manuals don't go back that far but I would suggest 10 - 15 Ft/lbs of torque. Wait for someone to post the exact specs if you can. Cranman, if you can make copies of your friends engine manual I would be happy to pay for one...
Clarence