Thanks for the help guys. This is a first start on engine that hasn’t run in awhile. New head gasket etc. No coolant in the engine currently. I was thinking and hoping it was oil passage way but wanted to be sure. Best plan of attack to tap it and plug or is there a crush plug like a frost plug that goes in there? Thanks again!
If it is the same as a 1F, the oil pressure sending unit thread size is 1/8" BSPT (British Standard Pipe Thread). You can purchase a 1/8" BSPT to 1/8" NPT adapter. If you are going with an after-market oil pressure sending unit, you van purchase an adapter. Toyota to Aftermarket Oil Pressure Gauge Adapter - https://www.yotashop.com/toyota-to-aftermarket-oil-pressure-gauge-adapter/ This adapter threads into Toyota blocks that have a 1/8"-28 BSP thread for oil pressure sending units. The threads are very close but not the same, trying to screw an aftermarket gauge into your block will do damage or leak. Use this adapter on Toyota 20R, 22R, 22RE, 22RET, 3VZ-E, 2RZ-FE, 3RZ-FE, 5VZ-FE and many more Toyota engine blocks that have the factory 1/8"-28 BSP thread pitch.
Well sorry guys I should have looked closer. The oil sending unit is NOT on the base of the oil filter pedestal on this engine. This 2F came out of a stock‘76 fj55. I just figured it was identical to my ‘77 fj40 2f. So I’m going to clean it real good and install a stock oil sending unit in that location and hopefully call it done!