R/T converter is a higher stall, it locks up at a higher RPM. It lets the motor rev higher and get into the power band faster.

 

And when you tow down the highway it doesnt let the truck go under 3000rpm

 

MMMMRice How did you fit those tires on your truck? They look awesome! I want to put 33x12.5x17 on my 09 QC4x4. How much offset are the rims? I want to put on wide tires without a lift or level. Any help would be appreciated.

 

I bought them from 04hemi, he lives a couple houses up from us. The wheels fit with no mods. Im not sure on the offset, i think he said -12mm