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The temp is heating up now, and my engine does not like it. The temp guage is pegged most of the time on H. I run my heater on high to cool it down a bit. I do not understand why it is running so hot. Whe we first built it, we had the recommended 195 degree thermostat, and it would almost overheat just sitting in the garage. So I moved down to a 180, and it lowered the temp some, but it is too hot. Will removing it all together help? The headders are not coated or wraped. Could that be the problem? I have no idea how old the radiator is. It is 24" long and 19" tall. Is this too small for a 351? Would an aluminum rad do the trick? Only other thing we can think of is that it is that the system has a leak somewhere and is not pressurized, so the water boils and does not cool it. When I had the 302, it ran very cool with the same rad. I really need to figure this out before I ruin something. I drained the tranny fluid and it was a browish-red milky color from being so hot.
Thanks for any help yous guys r the best.
Matt
 

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Dont remove your thermostat, it really wont help. First thing ya need to check is to see if the factory restrictor is still inplace under the thermostat. On most engines, the thermostat is the restrictor, slowing the water down so it can actually shed the heat, but on 351c, the restrictor is a seperate part under the t-stat. If its not there, your gonna have to find one. Anyone out there know where to get them? I dont think my 351 has it (runs hot in the summer, and my buddy doesnt remember seein one when he owned the car) I asked autozone once, but they looked at me as if I was askin for plutonium to run my flux capacitor.
 

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Your first step would be to verify exactly what temp the engine is when it is reading "H" on the gauge.There are a few different senders.If that does show it is running hot ,then a radiator cleanout would be next..
Hook up a temp capillary type gauge or find someone with an infrared temp gun to find out where you're at to start with..
 

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A little history on my 351C (8.9:1) cooling problem...
My Fairlane only allows s radiator with a 20" wide, 16" high core (unless I remove more sheetmetal). I started out with a stock 289 2-row radiator,3.55 gears, and 2000 rpm stall converter. At 3500 rpm (hwy speed), it would run 230 on a hot day.
I added a separate trans cooler and a shroud, but it didn't lower the temp at speed. I then removed the thermostat and hooked up the heater, and I got a 10 degree drop to 220 at speed.
Then, I went for broke. I put the stock stall converter in, changed the gears to 3.00 (to lower rpm's), added a '70 Mustang 3-row, 3/8" tube rad (same w x h), 160 deg tstat, and a Milodon alum water pump. On most days, it runs 195 at 60 mph, 205 at 75 mph. Yesterday (90 deg ambient air), it was running 215 on the highway, and it would get up to 230 at the redlight. Turning the heater on dropped the temp by 5 deg only.
In my situation, I think I need a larger radiator. I plan on using Crite's aluminum rad, which is 4" wider also. It goes for $245 w/o trans cooler, $345 w/ cooler.
I hope my info will be of some help.
 
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