1995 S-10 4.3 liter timing

Hello there, I was wondering if anyone out there could help me. I'm working on a 1995 s-10 pickup with the 4.3 liter V6. This thing will not run off of base timing with the bypass wire unplugged unless I turn the distributor and advance the timing. Here's where I am at right now. By the way, this thing has 207,000 original miles. I have the timing cover off with the #1 piston at TDC. The timing mark on my crank gear is at 12 o'clock and the mark on my cam gear is at 12 o'clock also. The rotor on the distributor is at the #1 spark plug wire. I have well over an inch of play in the timing chain so that is getting replaced. And I was also told that my distributor could also be shot, so I am replacing that as well. Now I am being told that when I install the new gears and chain that the cam gear should be at 6 o'clock and the crank gear should be at 12 o'clock, then I should turn the crank 1 turn and then put the distributor in with the rotor facing my #1 spark plug wire. Anybody out there ever hear of this? Why would you not put the gears in the same way they came out? What is the purpose of turning the crank 1 revolution and then installing the distributor? Help!