i got a 1972 harley ironhead engine sittin in a 1979 frame so i found some spoke rims but the rear wheel has a drum brake will that drum brake set up fit in the 79 frame its a differant swingarm. second question it seems like the rear tire is offset to the right about half inch or so im just wonderin did they come like that from factory there is no damage and was never in accident. the chain is straight so im kinda lost lol

 

The 1979 had a disk brake, and the chain used a dished sprocket on the rear. I do not know if you can make those parts work together; perhaps, if you can make some appropriate spacers.

It is common for the rear wheel on Sportsters to be offset; 1/2" seems like more than usual, but those parts were not designed together so ...

 

The number one thing you MUST do is set the hub inside the swing arm frame so that the front and rear sprockets align.
A straight edge across both sprockets will show you when they are aligned.
Any space that remains at the axle on either side of the hub gets a spacer made to fill the gap(s).
I make the spacers using aluminum bar stock with a hole for the axle bored through it.

Then the next item is to build your rear wheel.
You want to spoke it up leaving the rim centered inside the frame. This will most likely not have the rim centered over the hub and that is fine.
This is simply done by turning the nipples tighter to move the wheel in that direction, right after you have loosened the nipples by the same amount that are on the opposite side of the rim.

For example, if you need to move the rim over to the left a quarter inch............. First loosen all 20 nipples on the right side of the rim 1/2 turn each.
Then tighten all 20 nipples on the left side of the rim 1/2 turn each. Work in 1/2 turns at most and I find 1/4 turns are better as that gives you more control.
This moves the rim over to the left and keeps the rim running (almost) true at the same time.
When you get the rim moved over the correct distance, then do a final true up of your rim.
pg