Lots of good responses
I'll add mine
try using 40%
antifreeze and 60% distilled water. To much
antifreeze will make the motor run hotter. Been there done that.
My friend installed a rebuild water pump on his 351W. He set the motor up on my test stand to break it in and check for leaks.
It would run for 15 minutes and then the temp would go to 250 plus.
After months of trying different things he pulled the pump and found they (the company that rebuilds the pump) had installed the wrong impeller.
New pump and all was well.
Check your radiator size
Had one FE with trash in the return hose. It would overheat at idle but not on the hiway.
Cured a few with new high volume pumps.
Over drive pulleys are not for street cars!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
If your going to own a Cobra you should buy a good (not Sears $80 POS) infrared thermometer.
Check the temp on the base of the sending unit in the intake and compare it to the gauge reading. Most gauges are off 5 to 8 degrees. Some as much at 15 degrees.
Best of luck
My buddies and I have chased a lot of overheating problems thru the years.
Dwight
My motor makes about 480-500 hp. Which is heat! Lots of heat.
Last June on I-65 north of Nashville Tn. it took me 77 minutes to go 4 or 5 miles.
My car idled the whole time and never got above 220 degree. Most of the time it was 200. I have a 195 T-stat. When it got to 220 I just rev'ed the motor for a few minute and it dropped.
I wanted to do the Happy Dance in the middle of the interstate. No over heating problems.
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