Dyno'd it - not happy at all....

[Rev]

Dark 5.0 is right. It's a myth that increased back pressure in the exhaust sysem helps torque. It is true that too big primaries on the headers may hurt torque. That's because the exhaust gas velocity in the headers is too low for good scavenging of the combustion chamber, not because you need more back pressure in the exhaust system.

Rev