Power band and torque curve most likely changed. With the larger valves the bottom end torque could have changed. My 11.70 Pontiac felt like a high 13 second car because the torque curve was so flat.

Maybe butt o meter needs recalibration?

Allen Here's a novel idea, let's not throw a bunch of parts at the car hoping it will fix the problem and instead spend a little time diagnosing it first. Life was a little easier when I was just a wrench.