223 Water Temp "Holes"


Well-known member
Hey guys! Just got my newly rebuilt 223 back from the shop. While it was there I had to replace the cylinder head with another '63 head. The only thing I noticed different is that the hole for the temp sensor that is on the side of the head in the back is too small. I see some threads on this exact thing but no real results on maybe a different sender or an actual adapter. My old sender looks to be 1/4" NPT. The idea of drilling and tapping this hole larger after spending a bucket of cash on it makes me nervous. I can provide pictures tomorrow if that helps. I hear of people putting it in the thermostat housing and I do not have any open ports for that plus I would rather have engine temp not radiator temp.

Thank you in advance my friends!
After some searching on the Rainforest Website.....I did find a few 1/8"NPT water temp sensors. I will do some electrical resistance testing with a heat gun and see where that takes me.
Congrats on the overhaul! No more smoking out the followers. ☺️
Common galvanized pipe nipples from the hardware store?
After talking to a co-worker that is an old Mustang enthusiast he mentioned the 1/8" npt is a common one. I got two in the mail from the Rain Forest website and will hope that one of them works. The treads are correct at 1/8"

I had one of those step #1 something is wrong panic moments!