Hydro boost system on lifted trucks and heavy tires?

Yup, converted a hydroboost system onto the dart.
I don't understand pushing tires though because hydroboost is a braking system for engines that don't make enough vacuum.

Mustang has been using the system since mid 90s (that I am aware of) and every diesel truck has a hydroboost system. Also the old astro vans had them as well.