Re: Thermostat in 258
180 or 195 works fine, but don't go lower. As stated above, too low and the engine does not run as effecient. If you have a stock radiator with fan shroud...and its all working well, go 195. Most 258's that I have seen run right around 200-210 under normal conditions...that will also give you the best gas mileage.
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak