Yes, I believe that's the stock Temperature probe port.
Thanks. I like it. I've been running a hotrod L6 since 1978.
Adaptation for desert heat...
1] I use a Flex Fan. I know they're controversial now. Mine's US-made, 43 years old and still under warranty. Never failed. The fan has curved blades which scoop more air at low RPMs. As RPMs increase, the pitch of the fan blades flattens out. Not sure what the controversy is? Usually the opponents are in favor of fan-clutches. Too many parts to fail with that configuration, IMO.
2] I now use the wider-based V8 radiator core. Three tier. HD. Since the L6-sized radiators are no longer available, going to a V8 radiator is inevitable. You get a bonus of frontal area. The Passenger side radiator mounts must be moved out to the 3 - 5'' width. New brackets may be needed. Well worth it.
3] I keep the heater core in the loop also, as it's that much more cooling area to help. If my temp gaue is pushing 212*F, I will turn on the heater and keep both windows open, until it drops. [Hence the slang term ''Hot Rodders''.]
4] Thermostat is 195* I think. Don't eliminate it.
5] Coolant mix. I buy Prestone [green] full strength and mix down with distilled water. Two gallons = 4 gallons 50/50. I start with the half-n-half and then add water or coolant mix as necessary. With polypropylene glycol/water coolant, your boiling temperature goes up from 212F -- more coolant: higher boiling point. Always keep 2 or 3 gallons of spare water for emergencies. Five if desert off-roading. Flush the system annually if a daily driver. Watch the color. You don't want brown rusty water. Use the attached Prestone Tee till you get clear water, then drain and add coolant mix until green. Remove the Tee when satisfied.
6] I used to mount a Desert Water Bag on the front grille in extreme off-road conditions, but they've gone extinct for the US [LA] -made flax evaporative 1 Gallon bag. Too bad. Kept an extra for drinking water. It was always cooler than ambient and tasted sweet. Insane prices on EBay for them now.
7] Keep the engine bay clean with degreaser and frequent spraying off of the engine at the car wash. A greasy coating of road grime and oil retains heat.
8] Park in shade whenever possible.
9] Run at night if you can. Tucson cools off about 20 - 30* when the sun goes down because of the surrounding mountains. Phoenix is not so lucky and can stay hot all night.
Compared to the V8, the Chevy L6 is almost air-cooled for a start.
