Beefed up My six, need more power to the Rear

I think you would be better off with a 4 barrel carb like 500cfm edlebrock carb and a 904 or 4 speed trans i think the 727 robs 20 horsepower from the drivetrain not sure thought also make sure you have good gears 3.55 or even 3.23 you will get better torque with lower gears verse the 2.76