Depending on the condition of your front motor mount, it is quite common that there is a need to jack the front of the motor up slightly, in order to remove or install the belt. As the Model A belt is adjusted relatively slack to protect the water pump and generator bushings and bearings, a belt with a thinner profile, might not provide enough surface contact on the inside surfaces of the pulleys. You might have to slacken off the rear motor mount bolts, before you try lifting the engine. An additional spacer washer under the front motor mount yoke, might work for the future. Comments ?