go on ebay.buy a set of bench seat tracks for under $10.00.
take them apart and theres your spare rollers.
i am building bucket seat tracks as we speak.
after seeing a set sell last week for $280.00 i am going to experiment .
Thats what I was going to do but the ebayers cant tell me what slides they have have.Redfish said they have metal and plastic and they dont mix.I looked at my 70 challey last night it has the metal ones and the tracks are set diff.
The earlier tracks didn't have the plastic ball retainers. If you ask those ebay sellers to look into the end of their track assembly the can see the difference. The earlier steel retainer will look like a Z layed on its side or something like this l\l
As for making bucket tracks from bench tracks .. it's doable but not easy.
Good luck to all