The girdle is to help support the caps with preload from the integral bolts. Those covers are about 1/2" thick. I got a Moser 60 with a billet 1350 yoke utilizing u-bolts. Ask 'em. I had an OEM yoke spread a bit over the years on my Dart. It eventually pounded a cap out and I lost a driveshaft.

A Dana 60 will take a lot of abuse without getting too fancy. With the weight of a B-body and a stick, the extra options can offer some insurance, especially if it hooks. But I just like to be extra cautious.

Anything will break eventually, even with a milder combo. I had a W-2 360 auto Challenger footbraking as fast as 10.22 and 1.37 60' times in the '80's & '90's. Not a really big deal, but I literally put thousands of runs on an OEM Dana 60. This was almost all year, twice per week and sometimes 3 times here in Florida. Many track championships to show for it. I believe I broke at least one gear and one axle, but not more than two. The original gear was behind a 440/4-speed that the previous owner had.