Early 70's A'904 Torqueflite downshift

Unscrew the slotted rod a few turns and take it for a drive. You might have to do it a few times to fine tune it.
I checked that today, it will not allow much. At idle the linkage at the transmission is all the way back and at wot there is not much further it could move.
Could it be an issue with the governor pressure valve?
At what rpm is a stock torqueflite supposed to upshift from 1stvto 2nd when in drive? Mine now is 2,500 rpm.