can't because the post office goes by weight and doesn't give any breaks on it sorry. But if you look at what you save by buying them at an auto parts store or other store it's still a hell of a great deal.
I also have Factory Harley service manuals that I sell on cd, if anybody is interested you can email me at longhairedwhiteboy@yahoo.com with the manual you need. I don't put these manuals on listia. I have them going back to the 30's