The normal level of coolant in the radiator tank is about 1-2 iches below the opening. The tank look low but do not worry.
An original radiator was made for up to about 7 lbs of pressure (on a Chevy auto engine). The truck pressure was 0-4 lbs of pressure, depending on the size of truck. The over heating is most likely not due to the radiator cap.
How low does the fluid in the tank end up after it overheats and comes out through the overflow tube?
What does your temp gauge read when the engine overheats?
Is it possible that the fan on the 292 engine is pointing too high at the radiator?
Regarding the brakes, 3B's theory is reasonable but another culprit might be that the plunger in the master cylinder (or brake cylinders) is/are not returning after you apply the brakes. Do the brakes pull to one side (if not, it might be the master cylinder).
Tim
