Speedometer Adapter

I have a 65 barracuda 904 trans slant six. The transmission has the slip in "bung" and bolt down retainer. I am wondering if this adapter will work to convert it to a more common screw type speedometer cable. Mine is leaking at this point. If not does anyone know if you can replace the seals on the "bung"?

[ame="http://www.ebay.com/itm/TF6-TF8-Speedo-Housing-FREE-US-SHIP-Torqueflite-8-727-6-904-Speedometer-/300729706363?pt=Vintage_Car_Truck_Parts_Accessories&hash=item4604e3277b&vxp=mtr"]904 TF6 727 TF8 Speedo Housing Torqueflite 8 A727 6 A904 Speedometer | eBay[/ame]