Roller cams are definatly worth the extra money, ESPECIALLY on street motors. The reduced friction from a roller cam is negligable. The advantages are faster valve lift and closure rates. Have you noticed that high rpm, horsepower cams often make more peak torque than low rpm, torque cams? This is because the high rpm cams typically have more valve lift. The more valve lift you have the more torque you have. Flat tappet cams are severely limited on how quickly they can lift the valve (the edge of the lifter will dig into the lobe if it is too steep). With a short duration, torque cam, there is very little time to get the valve to full lift and close it again. As a result, lift is limited. Roller cams can bump the valve off of the seat much more quickly. Roller cams are ideal for street use because they have a shorter duration for a given lift which results in a broader powerband with more torque available at lower rpms. I think an LS6 runs a 204/218 duration at .050" with .550 lift. I think they have 1.75:1 rockers which would equate to .471" lift with a 1.5:1 rocker. I am running a Comp Cams Xtreme Energy cam. These cams really max out the lift rate capabilities of a flat tappet cam. but with a .050 duration of 212/218 I can achieve a lift of only .447/.454"