SSI has blanks up to 7” we have contacted them about valves they will do a minimum order of 8. I had to contact them because I have 7 new stainless 1.75 x 6.90 that I am replacing my titanium ones with. My buddy is thinking about going bigger valve so I am going to get his 1.75 so I will have a set with extras, I would sell the titanium valves but as I said I have no idea on the history of them. After the Fins problems I am shying away from them