Will a 1991 700 R4 interchange with a 1979?

The 1991 700R4 transmission can interchange with a 1979 transmission, but several factors must be considered. The mounting points, length, and torque converter compatibility may differ, so modifications might be necessary for a proper fit. Additionally, the 1979 model may have specific wiring and control mechanisms that differ from the later model, which can affect installation. It's advisable to consult a professional or reference specific compatibility guides for a successful swap.