widest rear wheel and tire on a 71 c10?

i have a 71 c10 that currently has 18" foose wheels on and would like to go up to a 20". the wheels i picked out are the Zenetti Throwback 20x8 in the front and 20x10 in the rear. Will a 295/50/20 fit under the back? the truck will not be bagged. it is lowered 4"s.

anyone?

thats exactly what i'm runn'n on my 72 and its lay'n rocker