I have Extreme Automatic's Stage 2 version in my'68 A-Body. It's the best daily use and weekend racing automatic I have ever driven. An injected 408 Magnum spins it with just over 500 ft lbs of torque. It transformed the car, and when combined with the efi; these two upgrades are the best thing that I ever did to my old Mopar.
I opted for a custom 3 carbon fiber clutch lock-up torque converter from Precision of New Hampton. When locked up in 4th, it drops the engine speed about 350-400 rpms. That's at cruising speed, but the converter flashes at 3700rpm under more throttle with the lock-up feature turned off. It's like having a 5 speed automatic in my Mopar.