You may have a 67(2 piece)and earlier balancer.

68 and up ARE NOT 2 piece although it may look like it.
The rubber ring should NOT MOVE at all.
If it does, its junk.

And yes, there is a woodruff key in the crankshaft that locates the balancer and keeps it from spinning on the crank.
MUST HAVE that.

As far as plug wires to wrong cylinders;

Doesnt really matter where #1 is on the distributor.
After you know the balancer is on correct and torqued to 160 FT LBS, turn over engine till #1 cylinder is at top dead center.
The balancer should be coming up on 0 at the timing mark.
Now look at your rotor and determine where it points in relation to the cap wire.
Make that your #1 cylinder. Then just go from there.
18436572

Remember, the drivers side is 1-3-5-7.
Passenger is 2-4-6-8.