You are just asking for trouble having a 7,000-lb truck with a big-block V-8 turning 30-spline stub shafts. We upgraded ours using Yukon 4340 chromoly 35-spline parts and new Spicer U-joints with the factory inner short-side shaft. However, our eBay long-side inner shaft had the U-joint holes wallowed out, so we used a factory replacement from Yukon. Cox had to grind the Dynatrac knuckles and custom spacers so the larger-than-stock Yukon ears would slide into the axle. We also needed to get dust seals because our old stub shafts didn’t have any.