Yes, you can use it with the stock transmission. I made the switch from automatic to Tremec 5 speed because I miss shifting and wanted better gas mileage. About 24 mpg with about 350HP at the rear wheels. I changed the rear end ratio from the 3.08 automatic to 3.55 to make the mose of the transmission as well. The red one is the modified one, the orange one is stock stock stock with 23K miles on her. Just getting broken in actually. Love the 77's. David