Shorter belt after bypassing Smog pump and A/C

Use a string and run it around the path for the belt that you will be creating after the AC and smog pump have been removed. Then measure the string and match it to a belt.

Using the string method, make sure the old belt in installed. Remember, if there is a tensioner you have so leeway if the measurement falls between two inch marks.

You can also get pulleys to put in place of the components you have removed and use the same belt.