Looking for a shorter shock

The original shocks on my '81 KZ 550 are garbage. Will not compress much at lightest preload setting. Since I am somewhat vertically challenged, I thought I would drop down the shock height a little. The ones on the bike now are 14". I was looking at 13.20" or 12.5". Has anyone here used the lengths, and if so did they work OK? Any issues?

Pic?
Steve

It is hard to know for sure without trying the particular brand and model shock you have in mind on the bike. You would need to know how far the shock will compress under full load / severe bump to know if there will be clearance problems between the tire and frame. You will also need to lower the front of the bike by raising the fork tubes to prevent handling weirdness. That 12.5 shock may be too short.