Yup, larger diameter, slower air speed at low RPM means lower torque. And LS auto has higher final gear ratio then Q plus transmission it self is much heavier and torque converter isn't helping any. The graph comparison of LS and Q engine shows that the Q makes more torque from the start to redline but I doubt it as theoritically Q should make peak torque at much higher RPM and has lower torque down the RPM range. Some LS auto owners reported noticeable gain but I say it's not worth it. But 5 speed owners it's a cheapest way to gain 20 rear horse power.