The guy I bought my 72 from had a 700R4 installed about a year before I purchased it. It shifted very hard and I forget who on this forum told me check out BowTie Overdrives. I got one of their kits for the downshift cable and it made a world of difference. One of the best improvements I have done so far. Smooth shifting for normal driving and when I hammer it the tires bark when the tranny hits 2nd gear.