Sinistersilverado

lol, well i've looked around for a rear to throw in there mean while and came across a g80 down the road. This is a posi rear with 3.73's correct? well its out of a 4x4 z71 and the guy wants $400 so i might go for it. i'm not too sure what these things are supose to run but from what i saw the truck odometer read 32,389 miles, meaning there shouldn't be much tear on the drivetrain. also how much of a beating can these g80's take? i keep hearing from numerous people that their very weak units. Does anyone happen to know if i have to cut a hole in my bed for the rear end also? i just noticed earlier that if i have a good load or if i'm to hit a good size dip my bed hits the top of the rear. i measured 1 3/4 inches from the top of the pumpkin to the bed.