looking for this part or conversion for it

[sheeley2000]

american standard mixing valve

[hj]

That is an American Standard "Push/pull" faucet. M-One,(Moneplumbing.com. 800-525-9223), if they are still in business, used to make a conversion unit for it, but I have not seen it advertised in the trade magazines for years. Parts kits to "rebuild" it are available a good parts supply sites such as "Brown's Partsmaster", aka "BPI".