turbo 400 kickdown needs?

[RonWT]

Hi folks,

I have a 69 c10 that has a turbo 400 transmission behind the 350. I am getting the transmission rebuilt, and it has no kick down or passing gear. They told me at the shop that my pickup does not have the switch required, can anyone offer up what exactly I would need to have a passing gear or kick down when I stomp on it? Is there any after market kits available or how would I go about accomplishing this?

thanks,

Ron Tilley