I would guess the 1-2 and 3-4 and reverse rod ends need adjusted. I know it sounds silly that all of them would be outta whack...but just read till the end.
There is a selector pin built into the shifter handle/arm that selects the indivdual levers when the shifter is rocked from side to side. Once the pin is in the hole in the outter shift levers be it 1/2 3/4 or reverse, then forward/backwards movement of the arm causes the rods to shift the levers on the side of the transmission. This is why both second and 4th are hitting (both rearward shifts) If the adjusters are on the rear part of the linkage rods, I would remove them from their shift levers and adjust all of them equal amount of turns rearward on the linkage(think "unscrew" a this point). If on adjuster pivots are on the trans end of the linkage rods, then adjust them towards the front of the car. This will cause the shifter to sit a bit farther forward in the neutral position. All linkage rods need to be adjusted the same amount or the shifter will not work properly. Only a small amount of adjustment (maybe only 1/2 turns, they are fine thread) Also check your transmission mount for flex/wear.
Most manf moved away from cross member, or floorboard mounted shifters due to rubber insulated mounts sacking out. Once the engine mounts and trans mounts get soft and sack out, the linkage would end up out of adjustment. Hence most shifters were mounted on the transmission tail housing in later years and then even configured to be single rail type like the TKO/T56/T5 ect. Think of how much of a PITA it was to shift an old "3 on tha tree" car after it had a lot of miles...
