by Steve » Tue Oct 31, 2017 10:56 am
Everything is a trade off. One chooses whats most important since you (rarely) can have everything.
Currently, you have a mismatch between the exhaust system and your current camshaft profile.
One is optimized for low-end torque and the other for higher RPM power. You need to decide which is most important for the way you drive the car.
1 5/8" headers will certainly improve the overall (mid-range & above) power at the expense of low-end torque, BUT those 120/104 cams are are not low-end torque cams.