help identifying slant 6

My 64 slant doesn't have a bolt. The 74 does because I recall using it to turn the engine over.

Usually "all the way" is until the inner edge of the crank pulley is flush with the end of the crankshaft, since the press or pulley & bolt the factory used would have bottomed out there. It couldn't have very many washers or the pulley center wouldn't fit over the locating snout of the water pump. With V-belts, you only need pulleys within 1/8" of perfect alignment, much more forgiving than multi-V serpentine belts which like to walk off the pulleys. Not sure why people pay $$$ for after-market serpentine setups.