Harley Sportster Rear Shock Swap/Conversion

I just bought a pair of 2004 Harley Sportster rear shocks to replace my aging (and not very good when new) dampers on my 1976 KZ400 D3. At first I thought they were supposed to be a direct swap, but when I got them home I found my shocks to be 12" from eye to eye and the Harley's 13.25". Then I read the archived threads on this board and realized that, at least for the 400, there is indeed a difference between the two.

What is the best way to get the Sportster shocks installed on my 400 considering the stock suspension travel? I.e., one problem I've noticed is that, right now, the bottom of the KZ stock shock almost hits my exhaust (also stock) as the bike sits relaxed on its center stand. I really like the stock look and do not want to change exhausts to fit on this stiffer HD shock.

Has anyone performed this swap on a stock KZ400 and lived to tell the tale?

Any help would be greatly appreciated.