I've run my Cuda at 3,000 lbs in the low 10's, high 9's for years without hurting the Hemi boxes. I had 2 of them. The gears would go back to Liberty for magnaflux and relug on a regular basis. If they said that the gear was cracked, it got replaced. They always sent the old gears back to me and circled the cracked areas. Eyeball inspection never found the cracks that they found until after they returned them. Magnaflux is a wonderful thing. Probably saved me from a ton of disasters. The right clutch goes a long way in transmission endurance. I think a 833 will work reasonable well behind a Hellcat engine with the right clutch. Power management like the factory software wouldn't hurt either.