What are your intentions with the bike? I you plan to restore it, keep it 100% stock and you can enjoy the restoration (my favorite part), ride it, show it, have it, and when you're done get your money and maybe more back. That bike restored can bring $10,000 if done nicely in 2008. Future value may/should go higher. The 1972 is the most popular year, it's the fastest, and the year they made 23,000 of them - no other year would ever come close. I remember the 1973 and the 1974 had about 10,000 made each year and the most rare is the 1975 which only saw 5,000 or so.
If a restored H2 is what you want, then you've got something you can build on - mabe $1,500, 2,000 tops. If it's a hotrod that you want to modify and cut up - look elsewhere. By the time you get that one done with a built engine, pipes, and carbs - you'll easily have 5,000~6,000 in a bike that you can't sell to anyone for half the price. No one wants to buy a modified H2 - it's rare. They can be made to be very quick, but you'll never enjoy riding one that's heavily ported as a daily driver. They have bad manners - no power down low, too much and wicked up top. Stock, they are "ok" and can be lived with, but I still don't like riding them when compared to a nice CB750 Honda.
I have 11 Kawasakis, so while I do prefer that brand, you have to "want" an H2 to have one and be happy with it.
Gordon