took the 4 speed to the track

That's not a stock trans. He has 3-4 face plated and 1-2 is pro shifted so my guess is liberty? has put some mods to it. That's the best you can do with a 833. Are you using an aluminum or iron case. When you start pouring the coal to the stock cases there is no 2-3 bearing support like a g force or jerico so case deflection and tooth contact area are diminished. The fact it broke in 2 leads away from a clutch issue and Tim is great and probably has you darn close.
An iron case might buy you some time, Passon cases are no help and break as quick as factory aluminum. I have also mikronited and cryo'd every part inside to buy some time but nothing can make up for 30/40 years of technology and better materials.
I love my g force, couldn't stomach breaking more hemi boxes. Jericos and stuff come up often on racing junk and eBay, just keep the eyes open.
Good luck, love the car.