/6 when hitting the accelerator...

If the spark advance failed the slant 6 will surely spark rattle under a load.
New cap ,points, rotor, for a 40 year old distributer is a waste of time and money. A reman'd ditributer is a much wiser coin toss.
Accerater pump is easy enough to check. Look down through the carb air horn and open the throttle by hand. If the movement doesn't produce a squirt.... there's your sign. :)
You dont have to totally rebuild the carb to replace the accelerater pump. Just wash the carb good with parts cleaner before you take the top off.
Use the pump, gasket, etc.. needed from the kit. Good luck