House was built in 1986. Need to replace the center diverter but Delta claims my current diverter was not made by them. I was able to replace the hot and cold diverters with Delta parts but I don't know who made the center diverter. I have a roman or garden tub. This is larger than a standard tub. Attached picture, closest diverter is my old diverter length 4 3/4" second diverter is the one Delta sent me but does not fit. Please help!

I would take it to a Plumbing supply store they may be able to help you to find you the correct one, or call Delta again and tell them that they sent you wrong one, good luck.

John

There used to be a company called "Valley Faucets". Their faucets and interior parts looked like Delta...

Go to local "Mom'n'Pop's" store, or ACE hardware. They have Stem Book that will ID this stem.