gap for a 350 motor

[69-Chevy-350]

Hey All,
I was going through my haynes manuel and I see there are two different gaps for the 350 motor. My truck is supposed to be a 69 V8 but I don't see that size motor for that year. Anyhow there are two different gaps for the spark plug. They are .035 and .045. The block is painted orange if that helps. the motor is a recent one replaced two years ago. Which would all you mech heads reccomend. I just finished the cap, rotor, air filter and I have the bed primed which leads me to my next question, What kind of paint would you recomend for the bed. I need something tough and that won't chip. I will have pics up tommorrow hopefully.