Help with black smoke

I recently purchased a 2001 f250 7.3 power stroke. I replaced injector 8 two weeks ago to fix a miss and everything was going well until I was pulling a trailer and I started billowing black smoke. I made my way home but now I have a terrible knock and constant smoke. Any ideas?

I ran a contribution test cyl 3 and 8 failed. I pulled cyl 3s injector thinking it may be cracked but the injector looks fine. Even threw in a spare just in case with no change. I haven’t pulled cyl 8 yet because it’s brand new and it has never passed the contribution test.

This is video at idle

Here is a video after warm

I’ve since pulled injector 8 and it looks fine

I bought a temp gun and cyl 4 was running way hotter than the rest. I pulled it and it had a crack so swapped it with a new injector. Now the truck doesn’t smoke much at idle but there’s still a slight mist of white smoke and when I drive it I can cover a wide street with white smoke. Before it had absolutely no white smoke any idea of what can be causing it? Cylinder contribution test shows that only cylinder 8 fails but as previously stated cylinder 8 has never passed.