I'm not sure what you mean by a manual lock-up converter? They make lock-up and non-lock-up converters for both the 2004R and the 700R4(early 700R4s use the same converters as the 2004R)
All 2004Rs and 700R4s came from the factory with a lock-up converter. If you use a non-lock-up converter you will need to change a valve in the transmission. If you use a lock-up converter you will need to have some way of activating the TCC(Torque Converter Clutch) solenoid. You could wire in a toggle switch(manual?) or use an aftermarket switch that senses vacuum etc.
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