The performance of Mobile Ad Hoc Network (MANET) utilizing dynamic source routing (DSR) protocol was investigated and analyzed. Different simulation scenarios involving different DSR networks were launched using the network simulator package NS2. The effect of Maximum-Header-Length (MHL) on selected performance matrix was studied for different DSR networks. The selected matrix involved the average end-toend delay, the average packet size and number of dropped packets. Results of this study showed the possibility of selecting dynamic value of (MHL) while keeping optimum network performance. However, this selection was found dependent on many network parameters such as network diameter, number of nodes and nodes transmission range. The selection of the dynamic (MHL) was made possible by direct relation with few adjustable parameters. These parameters represented the scatter of nodes within the network coverage area. Optimum (MHL) values suggested by this relation ensured the coverage of 95% of the network nodes and provided flexibility to network administrators for tuning them.