Shoebox pulling a Teardrop

[Don T]

First the question; the car handles the trailer fine but overheating is the problem, so is this doable or is it just too much to expect out of this car? Background is; 8ba with OD, 3.88 rear end. The bore was within tolerances when I got the car so I did rings, bearings, valves, crank water pumps etc. There is a 5 blade fan which I believe is aftermarket, about 18" dia, sitting about 1-1/4" back from the rad. This was a frame off so entire driveline has been gone over. I have about 800 miles on the car now but compression is sitting at 80-85lbs all across, I am assuming the rings have not seated yet as a squirt of oil in the cylinders brings it up to the low 90's. Block and heads cleaned using the rodding and flushing method, sand and casting wires removed, I believe it to be clean. Rad was checked out by a "old guy" rad shop (they still exist) and he indicated good to go. No problems running without pulling the trailer at any temp, have not tried mountain roads yet as none are near. Started with 170 stats that came with the car; changed to 160's; both sets of stats were/are working properly. I was suspicious of the temp gauge so added a mechanical gauge which has read-out in the car. Without the trailer and with the 160 stats temp runs about 170. Both gauges seem to be on the same page.

Pulling the trailer (guessing 800 lb) at 60mph at 70 F into a 20 mph breeze temp is 190; going the opposite direction it sits at 200. I pulled the rad and flushed it, left straight CLR in it for a day, flushed engine and rad. In this process everything ran clean, antifreeze was a touch brown but still very "green". Engine vac normal and steady, plugs the right color, timing right on. I have a nylon bug screen in front of the rad (it is clean and rad clean). I realize the screen is not going to help the cooling but I also need a safety factor. The results of these latest efforts are zero as I expected. At the 200 temp the car smelled hot. So I do not think this is going to work when the temp gets to 95 and the car even sees a hill.

So am I missing something or am I going to have to re-core the rad and add another core or change out to a higher capacity radiator? All thoughts appreciated especially from those who have been down this road!!