That "large vacuum tank" with brake lines is a Hydrovac brake booster. Yes, it can be eliminated, but you will lose the power brake assist it provides. Better put in some time at the gym doing squats- - - -your legs will need to be in top shape without the power brakes working.
The governor is there to prevent overspeeding the engine in the lower gears, especially if the truck happens to be equipped with a 2 speed rear axle. The engine can rev into dangerous territory almost instantly in the "low" axle range.
Jerry
