I am ready to install head back on original 1913 motor. I bought new head bolts from Langs and noticed they are about an 1/8" longer than the original and the shaft looks a little thinner than the originals. Which ones should I use?
How are the threads? Are they the same size? If so, you can use the new bolts. Be sure to clean up the threads in the block with a bottoming tap and blow out the carbon and dirt particles from the holes. I would put the head on top of the engine without the gasket and install the bolts. Turn them down till they touch the head. Do not torque, just see if they go all the way down to the head before they bottom out. If any of the bolts bottom out before they touch the head, grind off until they will go all the way down. If you grind any of the bolts shorten all to the same length so that they will be interchangeable.
After doing the above, install the gasket and torque to between 45 and 50 ft lbs. Starting in the center of the head and working out toward the edges.
After you warm up the engine torque the bolts again. Do this several times after warming the engine until they stay at the desired torque.