Secondary Metering Block - 2 circuit wo/ Power valve - Designed to replace stock cast metering plate Our billet aluminum metering blocks are machined to very strict tolerances then anodized for protection and good looks. CNC cut from premium aluminum and filled with precision parts, these blocks provide the ultimate platform for your performance carburetor. Standard calibration for out of box performance - designed to fit most real world street & strip carburetors. Simply add your jets to complete the installation.