[chumbucket]

Sorry S_G, but I don't remember what size it was. It was several years ago and sold with the boat. I used it on a 28' boat that weighed in at around 8900#. So, whatever size I ended up using most likely would not be relevent to your application on a V20. If you need help determining the correct sizing, most of the prop manufacturers offer sizing help on their websites or just call them. When you go from 3 blades to 4, there is generally a diameter or pitch change required and sometimes both. If you have a good marine store local to you, many will let you try them out and return them (provided you didn't damage it) until you get the right RPM's.