How to find/fit extensions for 3 prong tub/shower valve

Question

I have 60 year old bathroom pipes (just the verticals; horizontals were replaced) and I need to find extensions and handles for the 3 prong tub/shower valve (hot and cold with a center k**b to switch from tub to shower). I don't want to spend hundreds on new pipes and valves cuz it is perfectly good (This tub gets rare use..) So how do I find just the extensions and fittings?

Answer 1

The Kohler Coralais is one of the few three handle valves they make anymore i dont know if they make extensions but its a place to start