'69 Cuda Power steering coupler options

Problems!! After talking to Borgeson and getting the coupler I find that it is the wrong one. The Borgeson 036425 joint has a 11/16" spline side and my box has a 5/8" od spline. But as I was looking into things, I put the old coupler over the spline on the ps box and find that the splines on the steering box are worn. The coupler skips over the splines because of the wear. Likely from the coupler being bad and the digging into the splines. After cleaning it up I see how it is shot. So I believe that means I need a new power steering box. Any advice on after market boxes and anything I should consider regarding gear ratios, brands, etc?