This paper investigates the installed performance of the ETF40B marine gas turbine engine (MGTE) on SLEP LCAC. Historical estimates of intake and uptake losses for SLEP LCAC have proven inaccurate, resulting in loss of available power for hump transition. A recent computational fluid dynamic (CFD) analysis of the uptakes revealed a possible 1000% increase in actual uptake losses. NSWCCD was tasked to evaluate and correct these detrimental deficiencies. This paper documents the development of the performance testing and results. Specifically, NSWCCD performed CFD analyses of the uptake configuration, designed pressure/temperature rakes, developed a unique DAQ schema, and statistical analysis of the average engine based upon acceptance test procedures (ATP), and generation of new torque tables based upon the LCAC drive train limits.