Can this drive plate be used, or do I need to machine it? If machined ..how much can I take off without ruin? Looks like some bozo put a pipe wrench to it.
The only problem with those marks are the ridges they produce. If not already done, they can be smoothed out by wrapping a 1" width of fine sandpaper (at least 220 grit to start) around the shaft like a belt and pulling back and forth. You don't need to eliminate the scratches.
More importantly check to see if the shaft is shaped like a barrel. Many are. Bottom line-- the marks wouldn't trouble me, there are plenty more important things to check.
EG wear in the square hole where the ujoint enters, worn fingers and/or pins, enlarged holes where the push ring pins pass through, bent shaft, bushing ID within spec cracks, etc.
If the shaft is worn uneven, you can turn a good amount off the area that enters the ball cap. Leave the rest alone because the spring cup needs to fit right. Then have the ball cap rebabbitted to fit the machined end of your tailshaft. I've seen a whole of stock removed without apparent consequence.
Thank you Richard,