Effective management of loading and work flow is becoming increasingly important in manufacturing. However, research has not addressed the associated dynamic internal performance issues as effectively as possible. This paper investigates an integrated approach to input and shop floor control under conditions of controlled delivery performance. Several new mechanisms are developed, including a method of dynamically adjusting buffer sizes based on system loads. Lead time and several measures related to the level and distribution of work in the system are used to evaluate performance. Results show that performance can be improved by taking loading and work flow issues into consideration when input release, dispatching and buffer space decisions are being made.