driveshaft Length HELP ASAP!!

if all thats changing is the rear then you need to shorten the driveshaft you have .66 inches the centerline of the 8.25 to center of the yoke is 11.69 while it is 12.35 on the 8.75 thus a difference of .66 it your front spring hangers will let you you can drill the holes that much further back and weld up the front of the holes moving the rear back so your driveshaft will work if the wheelwells allow. cheap and easy.