The 68 didn't have part throttle kickdown that the 78 had and the front band servo is designed different. It'll work but since theirs a big diff. in them it's hard to say how it'll shift. May be sloppy shifting.
What year trans are you needing a valve body put in? If it's the newer one I have a good one out of a 76 I'll sell for $30 shipped in the USA. It's dusty from sitting so it'll need taken apart and cleaned. If you want me to go through it and do a thourough cleaning I can do that for $30 extra.
