Used aluminum water neck of thermostat housing for most 1967-70 Mercury Cougar or most other Fords with 390/427/428CJ engines. Cast aluminum finish. Comes with threaded hole for either a screw-in cap, or thermal switch. For use with common 2-1/8 inch thermostats. Correct for 1968-70 FE engines. Not going to lie, these will show some signs of electrolysis on the inside and where the hose slips on. Additionally, we notice that the threads get a bit rotted out where the thermal switch resides.
*Note - very early 1967 cars were still using the 2-1/2 inch thermostats. Cutoff was around November 1966.