1987 toilet - one piece, low profile needs internal parts. Anyone help?

I'm working on a no name 1987 one piece, low profile toilet with a stamp number of 2866. It's got an unusual brass connection and swiveling sub float after the filler valve that I've never seen before.
Anyone have an idea about this design or available parts?





I have removed the float and float arm in these pics.
Any help would be greatly appreciated!

I can't help much on what you have, and I don't want to rain on your parade. However, this could be some Chinese import that no repair parts were available for even back when. Perhaps on of the experienced plumbers such as HJ, Terry, or Redwood can give a more definitive answer. One thing is for sure, this is a water guzzler 3.5 gpf toilet. It may be that a new toilet is in your future. If so, please do yourself a favor and consider a Toto. You can cut your water consumption by almost 2/3 and have a state of the art toilet with the occasional replacement part available in every hardware store at a reasonable price.

The flush valve looks like an Eljer, or maybe Universal Rundle, model. But a Coast 1B-1-X fill valve will replace that OEM fill valve. It uses a diversion valve with a knob on it to provide the water for the rim flush and refill, instead of the float, and is a lot less expensive than any OEM valve. If the large clear plastic hose is too small for the port in the wall of the tank, cut it, and the existing white hose, off and insert the new clear one into the white one. Adjust the knob on the side of the filler to provide adequate flow to the rim to wash it down. As a sidebar, I doubt that that copper work is original. No manufacturer would produce an item with "sloppy" solder joints like those.