Temp Sensor and Mechanical Oil Pressure Line

[wayno]

One more wrinkle... electric fan - so I'll assume I'll need two types - one for my gauge and another for the fan? o

[ray_mcavoy]

Sounds like you have later model heads with the smaller 3/8" NPT hole.

I'm not aware of any temp senders that have 3/8" NPT threads and the correct resistance range to work with the factory temp gauge. There is a Chrysler sending unit (Standard Motor Products #TS-131) that has small 1/8" NPT threads that could be adapted to 3/8" NPT with a bushing. It has a similar temp vs. resistance curve to the OE GM sending unit but it's not exactly the same so your results may vary.

You might want to reconsider using the intake manifold for your gauge sending unit and using the cylinder head location for your fan switch. The intake manifold is the stock location for the temp sending unit on most 1967 & older Chevy V8 engines anyway. Here is a good write-up that discusses the differences in the intake vs. head temp sender locations --> http://www.madelectrical.com/worksho...p-gauge2.shtml

[jtrichard]

you might be-able to get a 1/2" tap and tap the hole in the head to 1/2"