Narrowing my own 8.75. Questions.

No hate here, but no I wouldn't try it. Axle shafts are very specially heat treated which welding negates. I really like to keep it in my own lane, a powerful car turns very fast when an axle snaps under full throttle. Other folks lives are at risk too you know. Cbody and truck axles can be cut and re-splined to Abody length without tossing a very questionable variable into the equation. Aftermarket axles are cheap too and even stronger than factory.
If you had a spool in the rear, I would agree with the statement about changing lanes but not with a sure grip or open differential. I've snapped axles-that weren't welded on by the way-while drag racing running slicks on a Duster with a sure grip and it just couldn't transfer enough torque to the unbroken axle to make the car turn. The engine reved and that's about it. I was able to drive it home from the track with one good axle by taking it nice and easy on the sure grip.