What size is the hole on the side of the head where the coolant temp semp goes?

thanks in advance

 

https://ls1tech.com/forums/showthrea...hlight=fitting

Some good info in that thread, check post #21. Not sure if that's correct or not, but it's a start.

What are you trying to do?

 

Thanks I will check that out...

I am running an autometer water temp sender into it...

 

https://ls1tech.com/forums/generation-iii-external-engine/503672-tb-bypass-h20-sending-unit-install.html

Check that thread out.

There is a plug on the passenger side head you can use for it too. Since both heads are identical, it will be on the opposite side. This way you won't have to mess with your factory sensor.

 

I am trying to get a fitting to adapt to the hole in the passenger head, because that is a nice clean easy place to install!

That is why I am trying to find the thread size...

There is also a Engine coolant drain plug on the driver's side of the block that could be used... According to the guy at my local dealership...