You can leave it out. You can hook vacuum straight to your distributor and it will be fine. There are two types of ports on your carb though, straight vacuum and one that comes on after a certain amount of throttle plate movement. This type is called ported vacuum. You can use either but straight vacuum will move your timing as soon as the engine starts running and brings you to total advance earlier.
So if you have any timing issues, or feel like it's lost some power, check the vacuum port you are on
And set your timing using a vacuum gage, not a timing gun. A vacuum gage will adjust your carb and your distributor to exactly what the engine calls for, not the generic factory setting. If you are not familiar with a vacuum gage and how to set time and your carb with it, Google it. It's way more efficient
