The shift points at WOT are controlled by the governor. The governor has springs and weights that can be changed for that. B&M has an inexpensive governor spring and weight kit that will help you tune that if you feel the need. It also has instructions to help you choose the weights and springs.
The governor's output is modified by the TV valve (actuated by the TV cable) for part throttle conditions.
Thing is, if you mess with the governor, you're going to be messing with the shift points in all gears. Same with the TV valve/cable.
The only thing that tunes an individual shift point is the shift valve itself. These have a spring that resists governor/tv pressure. So to do something with the 2-3 shift you will either have to change the spring on the 2-3 shift valve, or to put a shim behind it.
If you can find a diagram of your valve body, you will see where the 2-3 shift valve is. Usually the valve train and spring is held in by a tapered pin, and this pin can't be removed unless you remove the valve body. It goes in from the top.
The governor's output is modified by the TV valve (actuated by the TV cable) for part throttle conditions.
Thing is, if you mess with the governor, you're going to be messing with the shift points in all gears. Same with the TV valve/cable.
The only thing that tunes an individual shift point is the shift valve itself. These have a spring that resists governor/tv pressure. So to do something with the 2-3 shift you will either have to change the spring on the 2-3 shift valve, or to put a shim behind it.
If you can find a diagram of your valve body, you will see where the 2-3 shift valve is. Usually the valve train and spring is held in by a tapered pin, and this pin can't be removed unless you remove the valve body. It goes in from the top.