These Proflow Billet aluminium tapered spacers can increase flow through the carburettor or throttle body by as much as 110 cfm. Proflow Manifolds tapered carburettor spacers will increase torque, horsepower, and acceleration throughout the entire rpm range. Proflow offers these 4-hole tapered spacers in 4150, 4500, versions in silver or black anodised. This provides high performance consumers with the ability to tune their engines for the maximum performance on any application