Need help with factory Temp senders

[chaptr2]

I have a 1972 K/5 Blazer and I just recently took out the old tired engine and put in a freshly rebuilt 350 with some World Products S/R Torquer heads. My problem is that the factory temperature sending units will not fit in the S/R heads. The factory temp sender is ½ inch thread and the holes on the S/Rs are 3/8ths thread. I would like to use a factory style temp sender so I can use the factory in-dash gauge. Using an aftermarket temp gauge will be the last resort and I would like to exhaust all other options first.

I’m looking for some info on some smaller temperature sending units that will work with the factory gauge. Has anyone here run into this problem? Does anyone know the factory ohms that is takes to run our in-dash temp gauge or know of any smaller temp senders that will work?

Thanks….

Chaptr2