26 spline input failure

so as some of you guys know i broke a custom made d & d input shaft. so i have so pics of the the 26 spline input with custom 29 tooth drive gear. talked to d & d the week i broke it and they said yeah we can make that and it would be a three week wait so i said i will get back with you on that im look for one that is already made. so i looked and thought i found one a week ago and turned out it was wrong so i called d & d back last week and the guy says uh we dont offer that one any more and i was like 3 weeks back you could but now you cant he says we have had failures where the shaft would twist off the drive gear and we havent been able to find the perfect fix. so i am now back to a 10 spline 29 tooth drive which is a custom made input shaft to match the aftermarket gears inside the trans. so here are some pics of the damage








if you look in the center you can see where they stuck the shaft through the gear and welded it on the bottom. the welds twisted and broke

my car barely breaks 300 off the bottle. i was told from d & d and the guy that built it a year or so ago and the both said that part was good to like 600. but they discontiuned that particular one cuz of the failure and a welding fix failure. oh well but i have one that is all solid one piece no welds