What do these rotors fit?

[nwZfan]

I have two new rotors in my collection of parts that I don't know what they fit. There is a part number 16-00508 511-240 on the boxes. They are about 10 5/8" in diameter. The "top" is 5 7/8" in diameter and 1.5" high. My part number searches have turned up nothing. Seems like I tried them on my 240 years ago, but they weren't correct. Assuming I picked them up in a parts lot from someone. You guys have any ideas on how to determine what they go to? Thanks in advance

PS. I hope this is the right place to bring this up. Haven't visited this site for a long time.

Ken

Edited March 26, 2020 by nwZfan
Images added

[Zed Head]

Picture?  The common ones have casting numbers on them.

[nwZfan]

Looks like it may have a casting number, but can't make it out. See pictures.

[jonbill]

i think its a 260/280 disc.
part number cross references here:
https://www.yoyopart.com/oem/13921449/internationalparts-service-88012.html

[Zed Head]

Smear some white paint over those castings and the numbers and letters will show up.  Or rub with some sandpaper and the high spots will shine.  Pretty sure I see and S and an H and a 6.