Re: 77 stinger w/omc controls-how to change over cables
If you have the box with the black "pleather" armrest on the top and the warm-up lever is under the shift/throttle lever, then you need the '79 & prior cables. These cables do NOT have factory installed ends. You will need to re-use your existing ends, held in place by set-screws.
Remove the three Phillips head screws from the back side and the box should open up, clamshell like. You may have to advance throttle or shift to move the cables to a point where you can access them with your Allen wrench to undo the cable ends. Should be pretty straighforward once you get in there...