Matching brake disc to rim

[flynow]

How do I find/buy a brake disc to match my Cleveland rim? I bough old rims and the tag says 600X6 and underneath 4C (looks like a C). It's difficult to make out the model number on the rim, but looks like 40-24. Manufactured 7/65.

UPDATE- think I found it. Found a Cleveland Product Catalog and found the Model number which seems to lead me to disc 164-00900. Catalog is here: https://www.aircraftspruce.com/catal...heel-brake.pdf

Thanks

John C