I recently purchased this wastegate and the top has threads where I believe there should be a vaccum port but its empty. Here is a pic of the wastegate. Does anyone know if its used and if so where I can find one?
Looking at your pic, I have what I suppose is the larger HKS 60mm GT wastegate since it has six cap screws holding the ribbed cover and yours has only four. Mine has an adjusting screw with a locknut sticking out of that hole.