I have an old BIG gitzo tripod and head I would like to use for my 8X10 but the head only has a 3/8's stud. Is does anyone know if there is a 1/4-20 stud available from Gitzo? I can't find a model number on it anywhere, but it is a big pan tilt head with a large "table."

I did some googling and came up empty so I thought I would see if anyone here might know. One thought is that I could use a generic 1/4-20 knob kinda thing, but it would not be retained when you take the camera off.