This 1-inch spacer made of thermosetting phenolic plastic insulates your carburetor against multiple heat and keeps it cooler. It also prevents fuel (also known as a vapor barrier) from seeping away in hot weather. This can also enable a denser fuel mix to increase performance in some applications and provide additional plenum volume. The 4-hole design is designed for GM Quadrajet carburettors with 4BBL and can also be used with other carburettors in a spreadbore design. Gaskets, studs, washers and nuts are included.