This vacuum booster is a factory replacement for 1977 and 1978 F250 trucks with a cantilever booster assembly. Most all F250s from these two years seem to have this style booster. You can spot this style booster easily by looking under the dash near the steering column and seeing a flat bar connecting to the brake pedal.
 
These are a 10" and change single diaphragm, with an overall outside diameter of 11" and commonly referred to as an 11" booster.
 
These boosters have an excellent quality black powdercoat finish that will look great for year and years.
 
These boosters are specially manufactured to my high standards and quality control. They are superior quality to other lesser expensive options for sale. Every piece of them is 100% brand new and not remanufactured.
 
 
OEM part numbers this is intended to replace for reference: D9TZ2005A. This booster is pictured next to an oem used booster for reference.