ZZ502 Engine Cooling Help

[Woj]

Hi Folks,

I've got a 502 crate engine in my 69 Post Chevelle (Resto Mod) with an mechanical water pump and electric cooling fans. When I bought the car about 8 years ago, the cooling system worked ok, but it could get fairly hot on a warm day. Long story short, the cooling fans, electric fuel pump and ignition were on the same 20 amp circuit that eventually fried itself out and the car no longer ran.

A good friend rewired the circuit and put the cooling fans and fuel pump on a separate high-amp circuit. Everything worked great. However, the cooling fans worked too much due to a low temp switch. The engine was running cool (140 degrees). I went to replace the thermostat only to find out the one in there was rigged to full open.

Chevrolet recommends a 180 degree thermostat which is what I put in. I also changed the temp switch for the cooling fans to one that comes on at 200 and shuts off at 180. Unfortunately I could not get the fans to come back on.

Here's where my real question comes in. The temp switch for the cooling fans is in the intake manifold, with the thermostat at 180, should I get a switch that turns the fans on cooler than 180 or greater than 180? I currently have the 200 degree switch that did not turn on the fans. I did not test the switch to be completely accurate, but it is brand new.

I thought ideally, I'd have a temp switch in the radiator (like newer cars), but the only fitting I could put one in there is near the top and if the coolant is low I don't think I'd get a good reading for it to work.

I'd appreciate any thoughts from anyone that has gone down this road before.

Phil Woj.