non-standard size temp sender? Can't find right size replacement

[centuryhouse]

I can't seem to find a suitable replacement temperature sending unit.

I have a 72 GMC Sierra Grande 350 5.7 4brl 2wd - but from what others here have said, it appears the engine was replaced with a late 70s crate engine, which makes parts look-up difficult or impossible.

The 1/2" size threading on most replacements is way too big. Even Lectric's units are described as "they screw into the original size 1/2" pipe thread-size hole (not the smaller 3/8" hole)".

I also need the tab type connector, which appears not to be the type that comes on most.

I found this correct connector type at O'Reilly but the threading was too large:

http://www.oreillyauto.com/site/c/de...er+-+universal

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