Here is a small chunk of the info from NC, the oil pan is for temp not pressure, sorry about that:
This is the perfect place to tap in for pressure readings. Even Toyota thinks so. There's another location on the head for the 2ZZ-GE but I personally think this is the best location.
required parts :1/8" NPT female to 1/8-29 BSPT male adapter :1/8" NPT T-fitting :teflon tape required tools :crescent wrench or 24mm deep socket
Disconnect the wiring and unscrew the oil pressure switch. Remove any remaining Locktite residue on the thread and block. Screw the 1/8" NPT T-fitting to the 1/8" NPT-1/8-29 BSPT adapter before bolting it on the block. Bolt the adapter to the block. Screw in the stock pressure switch and the oil pressure sender on the T-fitting. Coat all threads with teflon tape.
Note: Be very carefull not to apply excessive weight to the T-fitting when screwing on the oil sender and switch.
Note: It would be wise to isolate the oil pressure sender from the block to avoid possible wear and failure. A high pressure hose and additional fittings are needed.
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