Myosin V is an actin based molecular motor that utilizes ATP to convert chemical energy into mechanical work. The converter domain plays a crucial role in the allosteric communication between the lever arm and the actin- and nucleotide-binding regions. Interestingly, mutations in the converter domain of human beta cardiac myosin are associated with hypertrophic and dilated cardiac myopathies. Thus, we have made the corresponding mutations, R712G and F750L, in the converter domain of myosin V to investigate the effect of these mutations on the myosin kinetics, structural dynamics, and motor properties. The R712G and F750L mutations did not change the actin concentration at which the ATPase activity is one-half maximal (KATPase) and the maximum ATPase rate was increased 15% in the F750L mutant but unchanged in the R712G mutant. In vitro motility assays revealed sliding velocities similar to WT for both R712G and F750L. Actin-activated phosphate release was increased (43%) in the R712G mutant, while the actin-dependence of phosphate release was disrupted in the F750L mutant. We followed the motion of the lever-arm during the ATP binding (recovery stroke) and actin-activated product release (power stroke) steps using stopped-flow FRET. The R712G mutation reduced the rate of the recovery stroke by 30% while the power stroke was increased by 60%, whereas the F750L mutation had the opposite effect on the recovery and power strokes. Mechanosensitivity studies demonstrated that both mutants are more sensitive to the addition of load in the in vitro motility assay. Our results provide direct evidence that the converter domain is crucial for lever arm rotation and we provide further evidence that the lever arm gates phosphate release.