I can tell you from experience that the last thing you need on the street is more low speed torque. My 6.1 run a Frank Racing Scud camshaft, .219/.223, .571/.574. It made 420FLBS to the wheels @ 3200RPM, 405HP @ 5800RPM and carries 400HP to 6900RPM! I shift at about 6500/6600RPM. I run the 855 5-speed/3.73/285/35-18 which are 26" tall. I can destroy my tires in first and second gear on the street!