Auto Transmission Shifting Issue Since 4bbl Upgrade

The 1st to 2nd shift is supposed to happen at 18 mph, and the 2nd to 3rd shift is supposed to be at 28 mph. That is just under normal driving conditions. The transmission won’t last long with no kickdown linkage. There was some for sale in the mechanical parts for sale section the other day, and it was 4 barrel linkage. There is a difference. Good luck.