How would one add a gauge like this to a SBC?

Oil temp gauge

Where does one mount the temp sensor/sender on a SBC? What size threads?

Thx!

Well, for lack of more experience chiming in, I'll get things rolling.

I can suggest two places that I could see it working. One would be putting a temp sender into the side of the oil pan below the oil level.

The other would be if you're running an oil cooler to put a sender in the return line from the cooler. That would be my preference since it would be the actual temp that would affect the engine durability.

I can't tell by the ebay link if the oil sender is included. it's definatly needed.

Maybe someone else will chip in to confirm...

I installed a 1/2 npt temperature sensor inplace of the oil pan drain plug. Purchased it from Classic Instruments (SN25). About $20. I used an original 914 oil temperature gauge.

Sender SN25

Brazing a fitting into the pan might seem to be the most logical place for the temp sender, but having it anyplace on the pan is also the most vunerable place, & is just begging to be wacked off by any sort of road debris - and the resulting loss of all your oil = bad news, IMO.

Most of the roadrace "T" design pans have provisions for a sending unit on the top of the "t" wing, which gets the thing away from the road surface & provides some protection. (wet sump circle track "L" pans put it the same place too, on top of the "L")

Assuming you don't have that type of pan, the only place I would feel comfy plumbing one in, would be the horizontal pressure feed bung right above your oil filter, which is probably where your oil pressure sender is (which is the worst spot to read your PSI, but that's another story). Put a tee fitting in the block with the PSI sender off one leg & the temp off the other and call it done (better yet, move your PSI sender somewhere further downstream). Not the best for temps since you're reading after the pump, but it'll be an accurate relative temp, & the sender will be much better protected than anywhere on the pan.

JMO, but that's where I'd plumb it in using a stk type pan & no cooler.

edit 2 add

Why...do you feel you want to monitor oil temps on a water cooled motor?

On a SBC water cools the top half of the engine and oil cools the lower half of the engine. I agree with Computer4kids, what makes you have a concern of the oil temp. Oil pressure is important to monitor that oil temp.