and if being made for use behind an OD transmission with 3.73 up gear set, high speed balancing is a must in my opinion. most implement and/or big truck places do only low [1000rpm or MUCH lower] RPM balancing. my one buddy had 3 different new shafts build by 3 different implement/truck places, all balanced, and complained about vibration issues. we unhooked everything including the engine, wheels/tires/brake drums, checked runout of both yokes and the shaft tube, plus runout on the transmission input and output shafts, and ALL of these were A-OK.
everything traced back to driveshaft balance. all three shops balanced the shaft[s] at 450-650rpm.
combo was GM LT1/700R4/3.92r&p with 27" diameter tires.
and yes, the pinion angle was spot on.
just my experience and opinion.