Right now whatever is a factory thermostat on a 260, assume 195. I may have a 160 but thinking a 180 high flow in the Performer going on the 350. Staying warm enough is not an issue on my 88, too warm is more the problem. I plan on getting a new condensor and A/C compressor for next year. Along with a GN flap kit, hopefully I can keep it around 200 max. I have blown a least one 40 relay plus the 40 amp relay board in a Flexalite controller. These fans draw some amps on start up. I have gone through at least 3 thermal switches maybe more. I have the low fans on a 20 amp illuminated switch direct wired to the battery with a 30 amp inline fuse. Yeah, too many failures to not have a manual back up.