Newbie with a question.....
I just dropped a 383 Stroker in my 71 Chevelle. Believe me, I have been having alot of fun. Here is my problem. Water temp at idle starts to rise. Sometimes up to 250 deg and beyond. I installed all of this before I fired the motor: a new 4 core radiator, new aluminum water pump with flex fan and original fan shroud, 180 deg tstat, new original radiator cap, antifreeze/water is approx 50/50 mix.

Motor is desktop dyno'd @ 450HP. CNC'd aluminum heads w/ roller rockers, air gap intake with 750CFM Holley, radical cam, 4 bolt main block, electronic ignition, mech fuel pump, shorty headers with 2.5" exhaust 50 series Flowmasters exit behind rear tires. Auto trans, idles at approx 900RPM in drive.

Electric gauge temp sender is next to the 180 deg thermostat. I installed a mechanical temp guage and got the same readings. I removed the thermostat and ran w/o. The motor ran at 150 deg and didnt change even at idle. At idle and in Drive, I put my arm down in front of the radiator, could feel the air flowing over my arm and felt adequate to me.

I do have factory A/C and I checked the condenser coil to see if it might be dirty or blocked, did not appear that it was. Does anyone out there have any suggestions?? I was thinking about installing an electric fan, but I dont want to start buying parts that will not going to fix my problem.

I appreciate any input you could give me!
John

 

Hi. First, get rid of the flex fan and replace it with a OEM clutch fan. The clutch fan won't draw all that much more power, if any, from the engine and it works much better. Then check ignition timing. Too much timing advance wiill cause a lean condition ( burning up all the fuel before the cycle is complete and then the engine is running on air without the right amount of fuel and should cause a fuel knock sound ) or You do not have enough fuel to maintain any distance run. Understand that when You put 450 horsepower into a car with a fuel system designed to feed 250 horsepower, it will eventually not supply enough fuel to keep the engine running properly. If Your car still has the factory fuel line and pump system, You need to upgrade it to match the fuel flow requirements of a 450 horsepower engine. Check the belt tension on the water pump. If it's a bit loose or slipping or if the water pump does not turn freely, then the pump will not be efficient. Enough with all of this, since the problem is at idle, the flex fan is probably the culprit.