This Holley Spreadbore Rebuild Kit Vacuum Secondary is for Holley model 4175. This is a complete carburetor rebuild kit. This kit includes non stick metering block and fuel bowl gaskets. Also, internal needle and seats, accelerator pump, vacuum secondary diaphragm, and 6.5 power valve. It also comes with the small o-rings, clips and gaskets that you need to completely rebuild a carburetor.