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I have a 77.5 w/ 400 in it. Current stat won't open, so.....
I have looked at many posts on thermostats. Robert Shaw seems to get the most thumbs up, but they are no longer made by Robert Shaw. They are made in China. So I see some guys use them and they fail. Next I see people talking about Stant, then motorcraft...
I guess I want to use one the has the Jiggler hole for bleeding air. I was going to buy a Stant, but see they don't have the jiggler. So do i just drill a little hole in it instead?
Does someone make a performance stat out there? does it come down to just pick one?
Make sure the one you get has a dome over the pin,not the one with the slot in the pin the and body is pressed into the slot.My over heat problem was the arm that was pressed into the pin broke and kept it from opening.Wasn't happy about that.Something like this
There was a failsafe brand in there when I changed it. (got the truck about a month ago) to start with. Was stuck open. also was a 180.
460me - the stant looks like the 1st one you have listed there. Thats the one i'm going to pick up today.
The 351C/M/400 takes a special thermostat with a kind of collar around it. A 192-5°F thermostat is the one to use. Use only the Cooper-Robertshaw thermostat. This has been discussed many times in the 335 series engine forum.
Where to buy a 335 Series thermostat
3 options:
-Find a dealer with a RT-139 still in stock.
-Robert Shaw 333-180
-Napa THM 297 After calling a local Ford dealer, I was able to track down a dealer that has the RT-139.
It’s a dealer in Kansas but they will ship it to you.
Bob Allen Ford 1(800)676-0675
I have a Napa 297 at home from when I was going to change a stat on my 79 F150 with a 400. I never did, just sold it instead.. I will use that one and drill the 1/8 hole for the bleed....
I still have a Robert Shaw 333-192 in my '77 from years ago (late '80s or early '90s era) along with a "FlowKooler" kitted water pump (they used to sell a kit with a disc that you riveted to the oem impeller) and I have a new 333-180 in a box ..... but I can't find them on the internet now.
I think I am going to order a MOTORAD 2023192 which is a high flow 192 and in some pics, it looks like it has the "hat" that drops to restrict the flow through the bypass in the block as the t-stat opens.
I also found that a Dayco branded DT66A is actually a rebranded RS 333-180 if you find one.
Good Grief! FlowKooler could get a Robert Shaw 333-195 stat for me, so I canceled order, then they just emailed me and said it will be shipped today... LAME.. I guess I will have the Stant and the Robert Shaw to choose from to put in...
Good Grief! FlowKooler could get a Robert Shaw 333-195 stat for me, so I canceled order, then they just emailed me and said it will be shipped today... LAME.. I guess I will have the Stant and the Robert Shaw to choose from to put in...
Oh? That's interesting.
The RS 333-xxx (180 or 192) is well worth pursuing if you run one of these 351m or 400 engines in warmer weather.
I know .... I've seen that gage start climbing on a warm day on the highway and slowly continue to creep up as the bypass remains unrestricted and heated coolant keeps going back through the WP into motor bypassing the radiator. It's a slow steady climb when it starts.
Like others, I drill a 1/8 or 3/16" hole in every T-stat I install if they don't already have a jiggler in a hole. Makes filling and draining and such much easier.
Ok so I just picked up a new tstat at napa, its a different #here in Canada. So I understand some of you drill a hole in it, can you show me where to drill. And what is the purpose? thanks for your input.
Ok so I just picked up a new tstat at napa, its a different #here in Canada. So I understand some of you drill a hole in it, can you show me where to drill. And what is the purpose? thanks for your input.
Its purpose is to allow trapped air to escape.. to "burp" the cooling system.
The hole is drilled in the middle of the flange face. Do a test fit and it will be evident where a hole can be located
Install it oriented at the 12 o'clock position if the thermostat position is oriented vertically... because air rises and needs to escape.
That's interesting. 
