X-CELerator SERIES: 360 degree, single-plane, open plenum manifold designed primarily for high-performancestreet, drag, marine and oval track use. With an effective rpm range of 2000 to 6500 rpm, this series works best with a higher compression ratio, 280 degree or more of cam duration and headers with 1-5/8” primary tubes. Being a mid- to high-rpm manifold, a standard transmission, or an automatic transmission with a 3000 rpm stall converter, is highly recommended. The carburetor mounting pad is designed to accept current performance aftermarket carburetors. The WEIAND X-CELerator Series is the ultimate street/strip performance manifold for single 4V applications where increased torque and power is required in the mid and high rpm ranges.