What year 235?
As Bill posted, a 160 degree thermostat was standard on 235s from 1954 up through the late 60s. Some manuals state that 235s went to 170 degree thermostats in 1960/61 when they also supposedly had 13 psi radiator caps (4 psi in 1954 and 7 psi in 1956 and later). I use 160 degree thermostats.
160 degree thermostats became fully open at around 180 degrees.
Most likely a 180 degree thermostat would not be a problem, but it most likely becomes fully open at about 200 degrees.
