I use a 160 degree thermostat and have the fan (electric) adjusted to keep the engine temp at 185~190. Seems to do very well in that range. The 235 has a nasty habit of building up sludge at the back of number 6 cylinder. There is a lot of slope to the engine and stuff naturally accumulates there. Hopefully this was cleaned out when your engine was rebuilt. This can make the rear of the block heat up and the temp sensor is back in that area, so it sort of skews things a bit. I also use a 3 row aluminum radiator and a 7 pound pressure cap. That and the electric fan made a big difference, but Davenport may be slightly cooler than DFW. We have summer about 300 days per year it seems.

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end