I have my cradle out for a DOHC swap. I have a 4 speed transmission. I went to pull off the sensor to see what type of O-Ring I had, and there was none. I have no idea how many miles this car has gone without an O-Ring.
I have both metric and SAE O-Ring kits. It looks like its an SAE R-23. I test fit it into mine just now.
R-23 or AS 568 217
1 - 3/16 ID
1 - 7/16 OD
hope this helps
[This message has been edited by marc-alan (edited 04-08-2021).]