A999 tranny same as 904?

I have a 66 cuda that i am going to be converting to a 360 car. Its a slant six car right now with a 904 tranny. I have picked up an A999 out of a 70s model car to replace the 904 with. Is it going to be a drop in and bolt up or will i have problems with linkage. Also, i have the slant 6 kickdown will that work for a v8? thanks.