what transmission to use with new hemi 5.7

I have the 545 in mine and I'm very happy with it. I put a Trans-Go shift kit, and a line pressure adapter ( bumps up the line pressure ) ( both less than $100) and this thing shifts like a bear. Yes there was some tunnel surgery, and had to fab a crossmember, but compared to the costs for some of the other options, It's a good way to go. I have 3:50 gears and at 70mph my motor is revving 2000rpm. Thinking of bumping up to 3:73's