This Holley Spreadbore Rebuild Kit Vacuum Secondary is for Holley model 4175. This is a complete carburetor rebuild kit. In this kit you will receive non stick metering block and fuel bowl gaskets. Also, internal needle and seats, accelerator pump, vacuum secondary diaphragm, and 6.5 power valve. You also get the small o-rings, clips and gaskets that are needed to completely rebuild a carburetor.