There’s 2 ways to covert. Buy the Arrowcraft kit and use the existing axle, but it might not have much reserve capacity left. It’s nearly as easy to just swap in a dually axle.
FWIW - I originally converted my can with the Arrowcraft kit. No issues with that kit, but my axle was a Dana 70 and was was still pushing a it 7,800# rating. One trip i spilt my diff carrier in half once when I jumped the van going a wee bit too fast, with a trailer in tow on a hitch extension. Then another trip I sheared the pinion gear, sending my driveline across the highway, when I did a 3rd to 1st WOT downshift with torque management turned off, when I went to pass a Honda Civic on a steep uphill while towing the travel trailer.
So now I have a dually Dana 80 axle. If I break this one, I’ll try the Dana S110 next, since my rear axle weight does top 13,000 pounds at times