Hi. Question I'd like to pose. I'm aware that the topic of engine temps have been discussed at length and it depends on various factors but I'd like to give a synopsis of what my current conditions are and let me know opinions of if it's on par.

It's a '70 Cutlass Supreme mated with the 350 and TH350 auto trans. XE268 cam (224/230 @.0050) with aluminum intake, Holley 750 DP and MSD billet distributor/Blaster 2 coil. Forged pistons, roller tip rockers, bored .0030 over, 10.25:1 compression with 93 Octane. MSD plugs and wires gapped to spec, factory exhaust manifolds (for now). Cooling is an aluminum Champion 3-row radiator with a 16psi cap (I think). Thermostat is a Stant 195. AC car but AC is not operational currently. Clutch fan with factory shroud.

Initial timing is ~13 BTDC with the MSD advance curved with the silver bushing giving 25 degrees of mechanical advance for ~38 total timing with vacuum advance plugged. AFR ratios are solid based on vacuum readings and the wideband O2 I have installed. Recently, this initial timing was increased from 10 BTDC as it didn't like it where it was but now runs great.

Temp range is standardly at 210 on both an evening drive with ambient temps of 77 degrees as well as daytime with ambient temps of 95 degrees. At a light, it occasionally climbs to around 215-217 but never higher than that and not at every light either. Just last week, I blew the bypass hose so I cleaned that up and replaced that hose and let the engine run after filling up with new coolant with the cap off for a while till the stat opened up in an attempt to relieve any excess air pockets.

Long winded question is with my current setup (and even most prior setups I've had) the temp has always been about 210, didn't really pay that close attention if it ever rose but since I blew a hose last week, I've been watching like a hawk to make sure all is good after the quick repair. I've heard suggestions ranging from get a lower stat, add Water Wetter, change fans, etc, but I really don't have any complaints about what I have, in fact I prefer it and don't want to add any additional additive to yield artificial results. I'm being told that those temps are 'too hot' but I suggested that with a 195, it opens at that temp and 210 is in range. I can't really address the climbing in traffic to 215-217 but I haven't noticed any adverse effects during driving. So playing devil's advocate, say I'm wrong and it is 'too hot', what should be done? Conversely, if it's not too hot and is perfectly normal for my application, what are types of adverse conditions I should be on the look out for to see if my temps are too high, aside from the gauge or puking coolant?

 

If it's "too hot" then try a 180 thermostat and see how the temps are with that. That's about the easiest thing to do.

 

What you have is normal for a 195* thermostat.

 

I was less than impressed with how well my Champion 3 core cooled my 403 in my G body. It ran similar to your temps with a 160 thermostat. Try a 160 or 180 thermostat. I put a 180 high flow thermostat in my G body with an A body Aluminum/Plastic rad to replace the 195 thermostat. It dropped the temps from 205-210 to 195 max, usually 175 to 180 now.

 

Sounds in the normal range to me as well. That said it’s hotter than I would like it. For the $10 & 10 minutes it takes I would stick a 180 stat in it & see what happens. If that moves it to 195-200 that would do it for me, if not, wth, try a 160.
If you drive the car in cold weather you will probably want to stick the hotter stat back in so engine warms up quicker & you get ample heat.

 

I agree with a thermostat change. Simple and easy ! I put a Robert Shaw 160 high flow in my .030 over 455 and couldn’t hit 200 degrees if I tried I think it actually runs too cool . I may try a 180. Your high temps in the mid teens aren’t horrible but if it were mine I’d like to see it a bit cooler . Sounds like a nice build , good luck 👍

 

I agree with everything that has been said. Your temps are not excessive but if you want to control the temps climbing while the vehicle is stopped, get a high-flow thermostat.

 

Update 8/5: Removed the Stant 195 and put in a Robert Shaw 180. Let it run without the cap for a bit in an attempt to remove any unwanted air. After capping it back up and letting it run for a while to check for leaks at the water neck, temp stayed solid at 190 with the mechanical gauge I have hooked up to the intake runner and never climbed past that. This was in a garage with only a shop fan running. I haven't driven it yet but that'll be next.

I took a temp gun and measured the top radiator hose and got 190, driver side of the radiator fins are ~175, passenger side radiator fins are ~150. Seems like it's doing what it should and it seems to enjoy the slightly lower operating temps. Do they sound on par?

Lastly, just as a reference, I took readings with the temp gun of spots on the aluminum intake and got 200 at the base of the coolant temp bung, 220 at a middle runner near the carb and 230 at the center just in front of the carb. My assumption is that this is normal as the exhaust ports are not blocked off so it's running both through the intake. Please correct/educate me if that assumption is accurate.

 

Sounds perfect to me. Yes if the exhaust crossover is not blocked then the manifold temp readings are in line.

 

How would I know what type of thermostat I currently have in my engine?
468 ci.

 

Without looking at it in your hand you can only guess by using your actual operating temperature.