Thanks all for the help and guidance. It's not that I want to increase the cruising speed a lot -- 50 to 55 is sure fine with me. Also the noise I can live with. But i don't want the engine over revving. So original engine is fine for me. I am most likely leaning towards changing the rear axle.
As for the color, it's not the original color and it's not done very neat. If it had the factory color, I would leave it alone. But I would love to take it to the events. For every maybe 700 vehicles in a parade, there I may be one Navy colored. So to break up all the green, I want to try this scheme first.
Edit March 2022: Ronnie added his truck to Gallery Forum' with the new color. Figured you may want to see the outcome. Added those pictures here, too. ~ Peggy M