I saw a Paul Shinn video on replacing the exhaust manifold gasket. He uses split rings, high temp sealant on both sides of the copper shrouded gasket, domed washers ( dome facing out) and 45 ft-lbs of torque. His video is on YOUTUBE. He also lets everything set overnight and checks torque again setting the wrench to 40 ft-lbs. Watch his videos...he is very enthusiastic about Model As and is an excellent mechanic like us.