53moneypit i am also planning to put a dana 70HD in the rear.
i do need the 4X4 in the winter to get up the hill to my house but also because everything on the stock front axle is worn out. i was measuring my '79 2WD GMC 1 ton front track width and it is pretty close to my '47. also the dana 70HD rear axle i have is an 8 lug so i would just use 8 in the front too.
48 big trucks i do have one like yours http://rides.webshots.com/album/563616467iqvoxl