This has probably been asked before. For a street/strip car with steel block and aluminum heads, what is best temp for highest hp and torq? I've always thought that cooler was better. Higher temps were mostly for emissions engines. Earlier MOPARS used a 160* T stat where as mid '60 models used a 180*. Which are you guys using?

Depends a bit on the compression ratio. I had a 9 1/2 to 1 compression engine that went faster and quicker with a 195 stat than it did with a 160 or 180.

For me I found block made a difference .
Factory 440 likes 165/70 drops power from 185/190 . @ 190 + def lost power .
World iron needs 175 minimum makes as much or more @ 190/195 . Just doesnt seem to lose power when hotter . Nice when you get in later rounds .
These are both pump gas motors , 440 - 10.75:1 , World 505 - 11.0: 1 . The factory block 505 was like the 440 iirc .

Tex

Look at dyno sheet water temps. Cool water, warm oil.
Doug

x2. You want warm oil to reduce the hp loss from the oil pump and for it to flow adequately everywhere it needs to go. And you want cold air temp because the colder the air, the more power it makes.

Engine wear is dependent on the temperature though, it's worse with cold bores and pistons. It starts leveling off and is negligible from 180*F upwards.

If it was a daily driver I'd run 180-195. My drag car gets warmed up. Right before the run the water is brought down to 140. Thats the temp it goes into the burnout box. At the end of the run is usually 160-170 depending on weather. Haven't seen any significant wear over the years. 1100 passes bearings always look pretty good. it has the same valve guides during that time. Still the same bushed lifters for 800+ runs. Currently it's got 300 runs on it. Hasn't slowed down, doesn't smoke, oil filter looks good when opened up, So the assumption is the ring seal is still decent.
Doug

I played around with mine a few years ago. My target temp for entering the burnout box is 140, I tried 160 and it slowed down a full tenth. This was in Oklahoma summer weather.

The only real change my car gets from street to track when racing at home is adjusting the fan controller to come on at lower temps. Fan on at 130 and full speed at 135. I can't maintain these temps running but I can keep it that cool in the lanes.

Hot oil, cold water and air

Alky needs a bit of heat. I have been staging at 180+ for many years. Alky takes so much heat out of the air stream , that it can"t vaporize as well if temps are low. Heat of vaporization is not as much as i thought, turns out it is more about the volume of fuel in the air. Methanol runs best NA about 5.1 to 5.6, blown/hi boost, down to 3.4?

What years did they run the 160?

I believe a 160* stat was used up til around ‘64 or ‘65. Not sure exactly.
I run a 160* stat. My system very seldom gets to that temp on the street. When racing, I warm the engine before staging to 150*, oil pressure at idle is around 50 psi. Burnout at 150*. Thru the traps, temp is at 160*.

Ally with steel heads ver alum head different temp???

I set up a dyno in my shop as a retirement present for myself. I have run about 100 engines in the past three years 350HP to 700HP range 120 to 130 degrees water temp makes the most HP. My NSS race car like to be at the starting line the same temp for best ET. I had an engine with a tunnel ram and two E-85 c arbs He told me E-85 liked 200 degrees water temp, NOPE, 125 degrees the best HP pull. At 200 degrees it was 30HP off.

Run the engine up to temp to heat the oil, use the coolant tower to bring the temp down to 125 and that makes the best HP, watch what the stock and super stock guys do when the have a heads-up race. They have a water chiller and a quick disconnect hose to bring down the coolant temp.

Reher/Morrison has good article on this. HOT OIL,COOL WATER. This article from tech talk #25

We have dyno tested literally hundreds of sportsman engines, however, and it appears that a coolant temperature around 120 degrees at the start of a run is ideal.

I recognize that Pro Stock teams have the luxury of 90 minutes between runs, and that it’s tough for a sportsman racer to keep the engine cool during round-robin eliminations. That’s just another reason to have an effective cooling system and to refrain from putting unnecessary heat in the engine by warming it up. Once the water temperature reaches a certain point, the cooling system can be overwhelmed. It’s like sitting in a traffic jam and watching the needle on your street car’s temperature gauge steadily climb. When it reaches the critical point, the cooling system loses its ability to control the temperature. The result is a toasted engine.

I’ve watched racers warm up their engines and then turn off the electric pump and fan to keep heat in the motor. My advice is to leave the pump and fan running to pull heat out of the cylinder heads, which need to be cool. You won’t pull much heat out of the oil because it’s sitting in the sump of the oil pan. Some racers believe that a warm engine makes more power than a cold engine. Others think that a warm engine is more consistent. In fact, heat is the enemy of performance. A motor will make more power if you run it cold – and it can still be consistent.

My recommendations to sportsman racers on surviving the long, hot summer are to use synthetic oil and run your engine as cool as you can.

It depended on where the car was being sold before the U.S. Government got involved with smog reg. in the late 1960s, maybe 1968 was the first year they, government and the environmentalist got involved on creating smog rules
Colder year round temp. states got the 180 F thermostats and the warmer out west of the Rockies, CA, AZ, NV, Tx. and maybe parts of New Mexico got 160 F thermostats, was what I was told by a Mopar Engineer at one of the old drag seminar they use to put on