160° Thermostats


i would like to change my thermostat ( standard ) for that one.

FlowKooler 330-160 - FlowKooler Robertshaw Series High Performance Thermostats - Overview - SummitRacing.com

or that one

EMP/Stewart Components 307 - EMP Stewart High Performance Thermostats - Overview - SummitRacing.com

Tried to order them with Summit, but the 2nd one has been cancelled and the first one is on backorder till mid of nov.

Both of them are Robert Shaw based. Wonder what the reason for the supply issue is. If anyone knows a adress where i can get them, or a similar product ( balanced sleeve design) any help would be appreciated




GT40s Supporter

Can't answer your question, but I have found that items back ordered at Summit are often delivered much earlier then predicted.

November is only a few weeks away.
the warehouse we deal with in the US has 12 in stock. I am putting in an order right now we will have it next week.
Cost here will be 13.00 GBP
Let me know.

Tom, curious why you are selecting a 160? Thanks
Hi Michael

two main reasons

I want the full cooling as early as possible and as early it makes sense (don´t want to run without thermostat). this long cooling circuit tend to be a bit slow in reaction, so i think this is working more like an integral regulator and by the earlier opening compensating the slowness of the cooling circuit a bit. Hope for a more stable and less up and down temp on a bit lower overall level.

Other reason is the balanced sleeve design in order to avoid that the water flow is keeping the thermostad from opening fully at high RPM.


Mike D

Lifetime Supporter
Interesting. Is this for a street car or track car? Are you concerned about oil temps not reaching appropriate levels to remove any moisture? I ran a 180 in a twin turbo diesel truck I used to play around with. I removed the engine driven cooling fan and replaced with small electrics. It turned out I hardly ever even needed them. It worked well. Let us know how this works for you. Thanks
If your cooling system is very effective, it could possibly lead to your engine running right at 160 degrees, which is too cold. Ford originally specified a 192-degree thermostat (I believe--I know that's true of the 351C, and presume it to be true for the 289/302/351W). NASCAR actually runs at higher temps because engines perform better up there--230 or 240 degrees can be the norm.

I run a 180-degree unit in my Pantera, and the car sails down the road right at 180 degrees. Right now Flowkooler can't supply 180-degree units, but 192 units are available (for the 351C). However, they can supply a wide range of 289/302/351W units. I would suggest a 180 degree would give the best overall performance to achieve your goals without letting your engine run the risk of running too cool.

My 427 Cobra used to run crazy cold all the time--140-150 degrees. I finally installed a 192 unit to get the operating temp up to a more reasonable level; now it runs at about 185 or so.

(Well, it did until I blew it up because all the oil leaked out and I didn't notice...) :cussing:
I have to agree with the higher temp. I think mine is either 180° or 185° and it sits rock solid right around 187° on the EFI sensor at the top of the manifold all day. In traffic (yes, I have driven it at rush hour) it might creep up to low 190's but when the fans kick in (currently set at 190°-ish), it drops right back to the mid-180's.

That was one of my biggest concerns with the car- keeping the motor cool. With the standard RCR rad and stock cooling components, mine is doing fine. This is with a FMS 6007-XB3 long block 302 with Edelbrock Pro-Flow EFI, rated for 350hp/350 ft*lbs gross.

160 is too cold for the engine to run at peak efficiency. I've heard it can lead to things like water/condensation buildup in the oil or wash out your cylinder walls with fuel/foul plugs since the engine will run richer at colder temps. I'm running a 195 in my turbo street car, and I daily drive in city traffic


Lifetime Supporter
Consider also the ambient temperature of were you are. Here in Texas you have some heat soak issues and you need to be able to catch the temp before it "runs away". Kinda similar to losing a building to heat soak over the weekend because some genius thinks that turning off the cooling wont effect the building when there is no internal heat load. Typically race cars use restrictors based on their engineers calculations and race conditions. They worry about base temp, wet bulb, humidity, elevation to tune the engine as well as the cooling. In Nascar the Roush Motors run a higher temp because they produce more power at that level. Just an example. My RCR P4 is set up with a 55 gpm electric pump and I am considering using a motor control to increase or decrease the flow to control temperature.
Hi Tom, In warm weather above 70'F, 160F thermostat works just fine, especially if in slow traffic. In the muscle car days, a 160F therm was the norm. On GMC 427 gas trucks, 160F therm was standard equipment for summer use. In the winter in Montana, we changed to 190's. I know this because I changed lots of 'em. The 195F therms are all about emmisions. If you insist on 195F, expect all underhood hoses, rubber items and seals to deteriorate in a few years. A hot engine also dictates the need for higher octane gasolines to stop pinging. Hotter engines have many more problems with "hot soak" conditions such as hard starting and may even experience vapor locking fuel lines in hot weather. For every 10'F increase of air tempurature, a resultant 1% horsepower will be lost. That is why your engine is stronger on cool night air. Nascar engines have a constant wash of air running through and over them, but GTs that run around town will get extra warm under the hood with a 195F therm. Nascar engines do not use thermostats, but restrictor washers of about 3/4" diameter. The washers are more reliable for their application. True, some Nascar engines do run around 200F, but they have very large cooling systems, lots of air and therefore can remove heat very effectively at the mostly constant engine speeds which they operate. Nascar engines use higher octane gasolines than we commonly use on the street engines, allowing for better combustion in a warmer engine. For a typical GT, a 180F is a good choice for all around driving. More importantly, race engine builders do want to see a minimum of 200F engine oil tempurature. The 200F to 260F engine oil temp range is important for good oiling. Best to install an oil temp gauge to keep an eye on oil temps. This has been my experience. Ranger Jim

i have quite a lot thermostats available no for testing. All of them are Shaw thermostats. in 160 and 180°, nonmdified and modified ( bypass holes in the membran)
will start with the 180° thanks