Time to replace the dorade boxes
Some people have used the Nicro solar replacement, which does not look like much.
And others have suggested Vetus, Plastimo etc
Naturally I would like not to have to drill new holes and to use my old cowl vents that i carefully repainted with white enamel inside and gold leaf paint on the outside (never tarnishes that way)
Is the opening to the cabin 3 1/2 ?
Some of the options are no longer made. Wonder if anyone has done this recently?
https://c34.org/bbs/index.php/topic,10913.0.html
https://c34.org/bbs/index.php/topic,10986.0.html
Both of them have a link to my tech note on the subject.
My replacement is shown in the 2nd link provided. I went with Vetus boxes and chinook vents. I considered the larger deck penetration but I elected not to. After living with the install for a bit, I cant see the hole enlarging to have been worth the effort.