This was placed as a reply in another post, but it seems to be a large misconception among many folks on the post, so I created a new thread.

I'm sorry my friend, I tend to disagree with your statement:

"You lose low end torque when you open up the exhaust on a stock car (especially 2 valves which already suffer in the low end torque dept). "

Most two valve engines put out excellent low end torque, (that's why they are so commonly used in trucks) 2 valve engines tend to suck on high end HP due to lack of breathing. When Ford put the 4 valve mill together in the Lincoln Mark 8, they actually created an intake controlled by the PCM to choke off intake runners to generate more low end torque. I don't know what they did with the Cobra, but I have noticed they are not that torquey off idle as compared to (Cobra guys step in) a 2 valve GT (both Stock of course) Many manufacturers have tried to address this in different ways, (the Honda VFR motorcycle uses VTEC technology to snuff two of the four valves at low RPMS. The ford Boss 302 with it's huge valved 4V Cleveland heads was a teriible driving car with the stock 3.55 gearing, 4.30's woke them up, the valves were so huge, the 302 couldn't tolerate the huge increase of flow when the throttle was opened, creating bog/low torque . The goal of every GT owner to improve performance, is to improve breathing, every Cobra owner as well, but they have to be a tad more careful on low end torque or they'll have to launch at a higher rpm/or gear down as many do/ or utilize FI/ to initially accelerate quickly. High torque snaps the car into movement from a dead stop. Despite all, if cost weren't an issue, there would be a Cobra in my driveway.

John