One thing I've done to my 75 F250 and the Valiant is use a high flow thermostat. It makes a big difference. So much so with the Valiant that the cooler 160 high flow thermostat helped knock a detonation issue I was having. I know some of the purists will cringe about a 160 thermostat but it made a big difference. Get the Stewart high-flow thermostat and get the 160. The theory behind it is, it will open long before the engine tries to see heat soak and keep it from ever trying to get there. It worked for me, naysayers be damned.
