Usually caused by worn distributor. Two degrees isn't bad at all. When it gets to around four, I'd replace the distributor, but first have the distributor checked on a distributor machine. Sometimes it's just a worn distributor (or worse, cam) gear.

If you have points on your 82 consider replacing them with a perlux or other point eliminator system that bolts on in place of the points and uses either a hall pickup on the stock point cam or a drop-in reluctor wheel, some of them even use an led optical setup. The advantage of the point eliminator is that it eliminates side loads on the distributor shaft from the points and can markedly reduce spark scatter, not to mention eliminate point wearout.