1967 904 Transmission spline

There are a lot of different kickdown arms and variations on the linkage. Start by setting it all the way back when the carb is all the way open. IF it shifts too early or too late, then you have to change the arm. Always start with the arm all the way back at wide open throttle (wot). I wouldn't get it if it's a lockup because the converters are expensive if you ever need one or decide to change it. Look at the front of the input shaft. IF the splines go all the way to the front then it's not a lockup. If the splines stop short about 3/4" and it's smaller in diameter and smooth; then it's a lockup. It's always a good idea to post pics.