Help me choose, I'm torn between a 160* or a 180* high flow stat. Engine is 1969 440 375 horse mostly stock except for a small Comp cam and Edelbrock performer intake, 391 gears. Car is a 69 Dart GTS so because of the small engine bay and big 440 motor not much air can circulate around the motor under the hood. What thermostat would you recommend? Thanks..

I think the 180 is even on the low side, DEFINATELY NOT the 160.

I run 160 in all of my pump gas streetcars, some run 180F+ and some run hotter
If you do short stop and go driving with trips less than 5 miles then it doesn't matter as it usually takes my motor more than that distance to get up to 160F
Cold motors wear, hot motors don't wear as much or as soon

I would suggest the 180 if you plan to drive the car (ie. not drag strip only).

Keeping water temp at least 180 helps reduce bore wear from condensing fuel. Also keeps temps steadier when running so the tuneup (mostly timing) can be dialed in correctly. If you run a 160 temp will be near 160 sometimes... and probably warm up to 180-200 sometimes under load in warm weather. If timing is set to avoid ping at 160 it may ping at 180-200. Similar effect on fuel mix and jetting. Actual temp under heat and load will depend on cooling system performance... a 180 stat should be fully open by about 185 degrees.

As long as your cooling system can handle the the load and maintain the temp, then you definitely want the 180.

I also run a 160 in my street cars, my big block stroker Duster runs at 178 degrees all day long with an aluminum radiator, flex fan, good shroud, and 160 stat.

I would suggest you also drill a small weep hole in the thermostat, I have had problems with air trap before and the thermostat won't open.

^^^ agreed, a 1/32 hole in the "flat" is plenty & also lets you pretty much completely fill it completely the first time as opposed to waiting for the stat to open. this elims a potential burp of coolant out of the rad neck onto your pristine eng & it takes care of hot metal areas that have no coolant on them when its first fired.

Just leave a heater hose off while filling the radiator and all the air comes right out, you can hear it. When the fluid appears at the heater hose nipple install the hose and fill the rest of the way. Done it for years on customer cars, saves lots of time and headaches.

I learned something today.

old dogs and new tricks, ehh Robert

today is my day

Uh, what about the air in the heater???

The heater has coolant in it already, just a little air in the hoses. Unless it is a fresh built car with everything dry. The tubes at the heater core are at the top of the core on regular heater B C & E bodies. Even if you flush it with the garden hose it still has liquid inside the core.

But Dave you are correct, any air in the heater core and hoses will still be in there. You can take the hose off at the heater core and do it but it makes more of a mess.

Just try it one time and you will see that it works well. Yes you may have to add some more after the stat opens, but it won't be another 1-1.5 gallons like before.

And if you waste time drilling a hole In the thermostat you still have the same air in the heater core and hoses, no difference.

I don't have a heater core or heater hoses in my car but whenever I change fluids I drain my radiator and both sides of the block, then I use an 'Airlift #550000' tool to suck all the air out of the system, then I stick the hose from the kit into my bucket of new fluid and it automatically pulls all the fluid into the cooling system with no air pockets. Best tool I've ever bought.

And I also drill a couple small holes in the base of my thermostat.

All this is good info, but I think we got away from the topic. What about the thermostat temp recommendation. Would you run a 160* or 180* stat? if you were me. Thanks.

at least 180 & on drilling the stat it takes longer to find/chuck up the 1/32" drill bit than it does to drill it. then I chamfer that mini hole with a slightly larger bit by hand, takes 5 seconds.

Running a 160 just delays the onset of heat. Might work as a restrictor once it opens and that might work out for you if it holds the water up enough in the radiator to lose the heat. I found replacing a 160 in a car I had made the oil stay much much cleaner. I put the factory 195 in it and it stayed right on the stat all the time. Even idling for long periods with no shroud.

The real deal is system capacity. Get that right and it will be fine. Engine masters did Dyno testing and a clutch fan without a shroud was the best engine driven setup. So I'd run a 180 or 195 with a big radiator and call it good. Get outside intake air piped in and you'll have a nice rig.

There is a lot of info on this subject on the WWW. Here is just one link, but it is consistent with most of the others and is easier to read than some others. What it says is that there is double the engine wear at 160* as there is at 180* with no appreciable performance gain.

And if it matters, I always drill a couple of small bleed holes in my thermostats. Which, after some bad experiences with other brands is only the Stant Superstats.

http://www.carnut.com/ramblin/cool3.html

Thanks for the link DaveRS, interesting reading. Most everyone here seems to agree, I should use a 180* stat for my application. I'm going to order a Milodon high-flow 180* stat tomorrow. Thanks everyone for your advice, you guys a great.