Finding a solid anchor point for the shoulder harness can be a challenge- - - -usually involving reinforcing a fairly large section of the cab sheet metal where the upper belt slider is located. If you use salvage yard parts, be sure the inertial pendulum that locks the belt during a sudden stop works freely and isn't rusty or damaged. Some states prohibit seat belts and/or parts from being recycled, especially ones from wrecked vehicles. "Use it once- - - -then trash it!"
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!