(X) indicates rebuilt items sold exchange only. The core charge is credited once we receive your rebuildable core. We just don?t clean and then put in new gaskets, we completely dis assemble carb, re-machine surfaces, ream new bushings for carb housing, install new throttle shaft, check jets to ensure correct, add all new gaskets and re assemble to original specifications. Resevoirs, servo units and hardware also available. Please call (888) 243-0440.