Figuring out how to plug most of the holes in the water rail hardware of the mid 80s HE engine being rebuilt. .
I am using an aftermarket EFI system so only need a couple of sensors, the heater hosetail and small coolant vent. That would be A, B ( or C), D and F.
Over 20 years ago building the HE engine in the coupe I made a note of threads and bought a lot of dies to make plugs and sensor bodies. The threads are shown also in the 2nd photo but may not be correct. There were a few differences in which bosses on the castings were actually drilled and tapped.
Anybody know for sure what the threads are I would appreciate an update.
Because the PO for this engine being rebuilt did not believe in using coolant inhibitor the threads are not in great shape so difficult to use a thread gauge to get the TPI.