Finned oil lines are available in two versions:
'74-'89 type: All non-'72 cars that are using the '74-'89 style thermostat should use the '74-'89 type, regardless of vehicle year
Pre'74 type: For use on early cars that are not using the '74-'89 style thermostat and all '72 cars. Pre-'74 type has male threaded fittings on the thermostat end. Male threaded fitting facilitate connecting to custom flex hoses enabling a range of termination options.
The Return line has the oil purge valve. For '72 configurations using the oil filter console with integrated thermostat, the Return line (with purge) valve should be connected to the thermostat/console.
See the External Oil Cooling Configuration Guide for more information.