Agree on the linkage adjustment as specified in the Chrysler Factory Service Manual. It might not be a big deal this time of the year, BUT that adjustment must be made when the carb is at "hot base idle" only, as the adjustment is based upon the throttle being in that lowest idle speed (i.e., normal idle speed) of about 550-650rpm.
Now, did this shifting issue begin suddenly or has it been building for a while? Has anything been done to the engine prior to this issue? Carb and/or intake manifold change? Which carb and intake on the motor now? Just curious.
In doing the adjustment, seems like there are some "gauge holes" in the linkage bellcrank mechanism at the back of the intake manifold? With the linkage unhooked from the carb pin, stick a small screwdriver into those holes to keep things where they need to be. Then check where the front end of the slot in the arm is in relation to the carb's throttle linkage stud. If everything "topside" is right, the slot should not slide onto the stud without moving the linkage rearward a bit. Like two thread-lengths on the rear part of the linkage rod.
IF the linkage adjustment does not change the shiftpoints downward to a min-throttle 1-2 upshift at about 10mph or so (check the speed chart for such in the FSM), then there might be an issue with the transmission governor.
Download a 1967 model year Factory Service Manual at
www.mymopar.com .
Keep us posted on how things progress,
CBODY67
it shifted fairly smooth before but the transmission came from another car only drove it a couple miles before it was pulled along with the motor and put in this car. it is a 2 barrel carb but could it make a difference if the kick down was set for a 4 barrel?
CBODY67