The master cylinder studs are 3 3/8" on center, which is correct for dual diaphragm cantilever boosters. If your truck has a single diaphragm cantilever booster (F150 and most F250), you can use this, but you need a new master cylinder.
This vacuum booster has an 8" dual diaphragm. It is meant to be a direct replacement for F350 trucks and a direct bolt in upgrade for F250 and some half ton trucks, with the exception of the master cylinder.
These boosters are not made with original tooling. They are very high quality built with modern 21st century tooling. They are functionally identical but they have a slightly different appearance than an oem booster. This has no effect on performance. The snout on the back side of the booster does NOT fit within the oem plastic sleeve that goes form booster to firewall opening. You can cut your oem sleeve down slightly for clearance, or remove it. Ford had three major types of boosters form 1968 to 1979. They had one main differences- the rods that connect to the pedal (or in the case of the cantilever trucks, to a lever). This listing is for the 1977 to 1978, and some 1979, version that has a short straight round rod off the back of the booster, and a flat bar that connects to the pedal.This booster is often referred to as the "dual piston caliper" type.OEM part numbers this is intended to replace for reference: D7TZ2005D
