I think you have a Box in her, by the sounds of it...
True Ames do a fantastic range of fins. The "Performer" starts at 5.45 Inches. I think they mean the equal of 5"7/16, or pretty damn close to 5"1/2.
Wayne Rich Power (6" onwards) & Small Box is also available in smaller sizes.
California Classic starts at 6" and is available in a wide range of colours and finishes.
www.trueames.com/
&
https://www.trueames.com/surf_select.php?surf_products_id=144&surf_categories_id=&surf_subcategories_id=&Performer%20By:%20John%20PerryDiscloser: I do
NOT have any association with True Ames. However, I do like their fins!

I have also ridden a bunch of their Single Fins (as Singles) and I have never spun one out. They are a pleasure to deal with. Send them an email, and the owner Chuck Ames is usually quick on the response, pricing, freight, stock, etc... They also have a close association with notable surfers & shapers in Santa Barbara area and beyond (I think they mean Channel Islands, and the Campbell Brothers who delivered us The Bonzer).
bonzer5.com/boards/bonzer-mechanics/The Venturi Effect, or did you mean to say the Ventura Effect!

