Fan timer after turn key off? B/C our 440 carb boils over mid summer.

I did this on a stroker smallblock Ford. I had two fans, each with a thermoswitche in the thermostat housing - one that went on at 90, off at 85 and one that went on at 95 and off at 90 (degrees centigrade). The cooler switch was on with ignition and the hotter was hard wired. Only used to run for a few minutes on hot shutdown. Worked well to stop it boiling over after shutdown and also stopped hewt woak in the fuel bowls.