Hear has been my thought on a stock bell housing versus a scatter shield. Drag racing, heavy car, high horsepower, high RPM are all reasons for a scatter shield. Stock drive train, mild street action, some autocross, etc. you can can by with the stock bell housing. It's a safety device, it is has a chance to fly apart where will it go......it's my feet so chose to protect them. The scatter shield market has become the place to go for transmission swaps like TKO's, muncies, top loaders and T56's to the mopars.
The best out there is the Quick Time, which sold a few years back to Lakewood. The run-out in the Quick Time scatter shield is very minimal with excellent quality and fitment. The cost can be the big deciding factor as a scatter shield can cost as much as $550.00. If you have the stock bell, it's a choice. Build accordingly.