Looking at a a833 tranny. Came from a '67 l was told. It has the forward shifter mount. What is involved in installing it place of a 3 speed in a '63 Valiant ? Car is a slant 6 and currently 3 on the tree but l was planning on going floor shift anyhow because l have a complete 230 setup. Any big hassles / hurdles in installing the 4 speed?