The specific years of the 727 transmission that will bolt to a Jeep 401 engine are:
* 1962-1971: These transmissions are known as the "A" series and have a three-speed automatic transmission.
* 1972-1980: These transmissions are known as the "B" series and have a three-speed automatic transmission with a lock-up torque converter.
* 1981-1990: These transmissions are known as the "C" series and have a four-speed automatic transmission with a lock-up torque converter.
It is important to note that the 727 transmission was also used in other vehicles with different engine sizes and configurations. Therefore, it is important to ensure that the transmission you choose is compatible with your specific Jeep 401 engine.