Help - Adjusting ‘67 904 console floor shifter

Sounds to me that the mechanical advantage of the shifter mechanism is a different ratio than the transmission needs.

In other words if you move the shifter rod 1 inch (just a number) the transmission needs it to move 1.5 inches.

The length of the shift arm on the trans needs to be correct to the needs of the floor shifter.

A way to measure this...

With shifter linkage disconnected put the trans in park. Measure from a fixed point on the car to the center of the shift lever on the trans hole. Then put shift lever into low and measure again.

The difference between the measurements is the travel.

Do the same for the shifter

That gives you the travel the shifter is looking for

Modify the trans shifter lever to get the same travel as the shifter.