My totally stock 2bbl '67 390 is in need of a new thermostat. I live in New England and its get pretty cold here in the winter and pretty hot in the summer. What do you guys recomend for a temp thermostat? I also need a new radiator cap, how many pound pressure cap you think is best? This engine is in a 72 F250 4x4.

Thanks
Jeff

 

I run A 195 degree thermostat and a 15 lb radiator cap.

 

>My totally stock 2bbl '67 390 is in need of a new
>thermostat. I live in New England and its get pretty cold
>here in the winter and pretty hot in the summer. What do you
>guys recomend for a temp thermostat? I also need a new
>radiator cap, how many pound pressure cap you think is best?
>This engine is in a 72 F250 4x4.
>
>Thanks
>Jeff

With you living in New England, I would go with a 185 thermostat (just to give you heat faster). If you park your truck in a garage I would go with a 195. And a 16 lb pressure cap if you have the resevior for your overflow if not use a old style cap with a pressure bleed off. The valve you lift on the top of the cap. Most people use the 195 thermostat. I hope that helped. Jack

 

Jeff, go with the 195 t-stat and a cap with the same pressure that's on there now. The thermostat determines at what temperature the coolant is sent to the radiator. An engine with a 185 degree t-stat will begin sending coolant to the radiator when the coolant in the block reaches 185 degrees, where as an engine with a 195 will obviously not begin cooling until 195 degrees is reached. So a cooler t-stat will begin cooling faster than one with a warmer rating.
Gasoline engines run more effeciently at 195 than they do at 160 degrees. The difference between 195 and 185 is pretty insignificant, but I think OEM was rated at 195 degrees.

 

Jayson gives good advice!
William in Atlanta

 

I'm in Michigan, and the temp here is 6*F today. I have been running a 205* stat with a 12lb cap and no troubles......and the heater works VERY well. DF

 

>With you living in New England, I would go with a 185
>thermostat (just to give you heat faster). If you park your
>truck in a garage I would go with a 195.

Your heater core is fed directly from your block. The temperature of the water in your radiator has no effect so you should not use this as a basis for determinig what thermostat you should use. I used to run a 160 stat but then just to prove DF wrong about colder engines making better power I switched to a 195 thermostat. I proved myself wrong in the process. It runs much better with the 195. Also the heater will blow you out of the cab.

 

Thanks, William!

 

Contrary to the post by ratsmoker, I ran a 195 thermostat, changed to a 160 and noticed a considerable performance increase with the colder thermostat. Maybe differant air fuel ratios make the differance when changing thermostats? This engine ran pretty lean.

86 F250 4x4,4.10 gears,4 speed, 10.25 rear, dana 50, 460, weiand stealth, edelbrock 750, heddman headers, 36" super swampers

 

I have a 1975 F-100 drag truck with a 460 that has about 700hp. The first time I raced it, I was cooling the engine down to 150*. I have electric pumps and fan, so I can do this with engine not running. In bracket racing, you want to make everything consistent. I always charge the batteries, cool the engine down to 150*, and fill the fuel tank back to a certain level. I was running 6.15@109 all night and had went 8 rounds and was down to 8 cars. It was 2:00 am and I was tired and didn't want to fool with cooling the engine down or charge the batteries. I got back in the truck, pulled to the line and noticed the engine temp was at 185*. I hadn't cooled the engine down, so now it was warm. I made the run and broke out because it ran a 6:13. When I got to the end of the track, I was at 225*. From now on, I only cool it down to 180*. In my truck, the warmer the engine is, the more power it makes. I've always went by the principle of the bottom end being in an oven, and the intake and carb being in an icebox. Just my .02. Dave

 

I couldn't agree with you more.

 

 

re:ratsmoker 160 vs. 190

My truck has been running terrible and just "not right". So, I decided (after reading your post) when I did my valve covers and hoses to also do the thermostat since I was not sure there was one even in there.

It had a 160, I changed to 195. Not only is the heat much better, the truck runs much better cold without backfiring through the carb. Now I am going to try tuning it again to see if I can ween it off 93 octane.