As I said in another post, I have never seen a TH400 with an electric kickdown, it's vacuum operated and the speedo should be mechanical too. Maybe some of the very late models before they went to overdrives, but not any I have ever seen. As far as bolting to your 400 SBC, no prob, for that fact should bolt to any SBC. You will have to have a driveshaft made probably, but that is not a big deal usually either. Being that new I guess it might have an electric speedo, but this should be pretty easily converted also.