351W stroked to 408, overheating

[HighPlainsDrifter]

Hi,
Right off the bat you're water temp is at 210 ?
That's too high, put in a 180 thermostat and drill a small 1/8" hole in it so air will bleed out. While your at it make sure you have the correct water pump, they can rotate in either direction, depending on year. Take the rad cap off when engine is cold and start it. the water should flow from the top hose and go down through the rad.
Take a timing light and check the static timing of the engine. Pull out the small black shorting plug in the distributor wiring first or the computer will advance the timing and give you a wrong reading. The static timing should be at 10 degrees BTDC. Your superchip should give you all the advance you need so don't advance the initial timing to 14 or 16 degrees like some guys do.
If you still have a catalytic converter on your truck, it could be plugged or collapsed inside, if it has more than 50 k on it -replace it with a high flow one.
You will need to check these things 1st or have someone check them before you spend money on a dyno or engine analyser.
Good Luck,
Perry.