Change thermostat from 160 to 180, or 190?

[Murd]

I’ve got a carb converted 88 Mustang short block, gt40y aluminum heads, edelbrock performer RPM intake, Holley 650DP carb, New FFR radiator.
When building it my research had me settle on a 160 deg thermostat, don’t ask my why but seems to be the performance suggestion out there for a carb 302.
Runs at about 80-85c (175-185f) in hot weather. This fall, driving in cold weather, down in the mid to low 40s, I was seeing temps as low as 65c (150f) while cruising on the Hwy with the heater on, and would only get up to the 80 range if I let it sit and idle or drove really hard and a good turn road.

I believe this is too cool for the engine to run well correct? Wear and carbon buildup if it’s too cool? Other obvious problem is I get minimal heat from my heater when it’s running so cool.

I’m planning on switching to a 180, any reason not to? Any reason to go with the stock 5.0 efi 192deg(or whatever it is)? That seems too warm for the carb engine.

Feedback appreciated as always.

[j.miller]

With the metallurgy of today 180-190 on a carb motor is better for the motor. The rings seal better and parts tighten up to spec.

[Murd]

It’s a stock 88 short block. Original rotating assembly and rings. 100k miles in its original mustang stock setup before I built it as it is now with new heads and carb, so presumably used to run the 190 in its former life.

I’ll try 180 unless anyone thinks I should be running 190+?

[wallace18]

180 will work fine.

[David Williamson]

with modern oils and cooling systems I can't see why anyone would use anything other than a 190 F thermostat - the engine is designed for it.
there is a reason new cars easily run way past 100k miles, back in the 60's & 70's that was unusual
David W

[tonywy]

180 degree thermostat will be fine. Car manufacturers use 195 stats for quick warm up and emissions. I think 160 stats have there place but, not in street driven cars in the fall.

[rich grsc]

with modern oils and cooling systems I can't see why anyone would use anything other than a 190 F thermostat - the engine is designed for it.
there is a reason new cars easily run way past 100k miles, back in the 60's & 70's that was unusual
David W
And here we have the CORRECT answer.

[CraigS]

I have to say I run a 180 but, I don't have an argument against the 190. I also stick a piece of cardboard across the bottom 1/3 of the rad in the winter. Otherwise, same as you, can't get it to even 180. I stick it in there w/ a piece of tape across the bottom to fasten it to the aluminum. It stays just fine but, if needed, I can rip out and throw it in the trunk.

[davekp]

I have to say I run a 180 but, I don't have an argument against the 190. I also stick a piece of cardboard across the bottom 1/3 of the rad in the winter. Otherwise, same as you, can't get it to even 180. I stick it in there w/ a piece of tape across the bottom to fasten it to the aluminum. It stays just fine but, if needed, I can rip out and throw it in the trunk.

What crank pulley are you using- standard or underdrive?

[CraigS]

Standard

[Bob Cowan]

Studies done in Alaska showed that coolant temps <160* cause accelerated cylinder wall wear.

[Murd]

I haven’t tackled this yet.
Everyone seems split between 180 or 190. Most ive read about carbed engines seem to be talking about running cooler.
Any potential issues running the 190? Too hot, vapor lock, boiling fuel in bowls?
So far it’s run like a top on the hottest days, I do have a carb spacer. 190 is probably about as hot as I’ve seen it run ever, not sure if I should expect it to run much hotter than that with a 190 thermostat?
Thanks!

[Houdini]

carb spacer is good to keep fuel from boiling

the best reason to run a 192 degree stat is for fuel injection to get good mileage

I run usually 180 degree and have extra coolers under car and usually run a electric pusher and steel puller fan
traffic and air cond can cause 20 degree temp rise


I used to do stock cars long ago and that had a quick learning curve to getting temps down below boiling