Making The Weak 7-1/4 Rear Axle Live... Kinda

Howdy!
I have a challenge for my self and would like some constructive input.
I'm building a 318 for my 73 Dart, it should make somewhere in the ballpark of 300HP. It will be bolted to the A904 auto transmission with a stock-ish stall converter. The car's weight is somewhere around 3450 pounds with driver.

So, I don't have a stronger rear yet, so the challenge becomes making the 7.25 rear hold up in the meantime. So far I know the spider gears in the diff are pretty weak, so let's start there. I have some ideas, like:
Welding the spiders together.(May not be good for street use)

Somewhow converting the open diff to a LSD.(Will be lots of research to be done for cheap)

Tuning the car to accelerate softer from a stop.

Not driving like an idiot.

Now before anyone replies with "Go buy a Dana 60 or Ferd 8.8" please understand that this is for fun and I'm not running a torque monster of an engine.
The welded spyder gears are not for street. Making turns, especialy right, it will tend to hop and chirp the inside tire. The car will want to go straight instead of turn.
An earlier Dakota rear with 8.25 may be an easy conversion. I know they are not overly strong either, but better. Just that road apples 6 bolt pattern they used. Get the axles redrilled for the 5 on 4.5 pattern. Some came with Sure Grip. Later ones even have disc brakes.