Its an internal clamp, not an external one. Was told that a traditional seatpost wold not work since it has not external clamp and not enough space on the frame to cut an opening to make a clamp work. Trying to locate an original part for this but any ideas would be helpful.
Oops, you're right. The OEM seatpost was a SunTour Expander, 27.2 mm. These seatposts had a quill wedge to secure them internally to the seat tube.