Ok major help needed . Yes, I'm still doing the LT1 conversion ( don't ask why still ). My problem lies in the temp. gauge . The engine runs for, say , 5 minutes when BOTH fans kick on. As soon as they do, the temp. gauge pins . I know there is no way that the engine has gotten to over 280 in that short a time !

I'm using a DeWitts radiator with dual electric fans . The temp. sensor is in the right head . It is wired to both relays .Also, the temp. gauge is wired to that same temp. sensor. I've checked and rechecked all the wiring and it is exactly as DeWitts diagram .

Anyone who's done this conversion, or is really up on the fan set up/temp, gauge , please let me know what in hell is wrong .

Oh, and before you ask if the temp. gause goes up gradually before the fans kick on, the answer is NO .

Thanks for any and all help !!

Bill, if you have the temp gauge wired in to the same sensor as the fan relay, it will peg as soon as the relay comes on. This is why the gauge doesn't register until the fans come on. What you have is a sensor that is open/closed at a certain temp, to control the fan(s). You should have two temp sensors; one for the fan/computer input(on-off only), and one strictly for the gauge, which is a variable resistance type.
Hope this sheds some light on the prob.

Oh ? Well, that shows how much I know   !! Now, my question is : Should I put another temp sensor in either head, or, put it in the water pump ? If in the pump , wouldn't that show a different temp. than in the head ? I understand it will be, at least 10 -15 degrees different . Am I wrong on this ?

Thanks for the heads up !!! Always good to ask the " pros "

The sensor is usually on the right cylinder head.   The fan is usually mounted on the intake near the thermostat housing.  But you can put them in any location on the head or intake, as long as they are in the water jacket, and it will operate okay.

I would put the sensor in the head. That's where your most concern abut temp. is. There should be a port just above spark plugs. If you put it in the water pump yes you will have lower temp. as the water has just passed through your radiator. Hope this helps. Terry