"the VCT didn't have anything to do with the 5 more HP the VCT was strictly an emission thing the 5hp came from the change in design of the stock intake setup."
VCT let Ford use more aggressive cams in an emissions controlled engine. Compare the ZX2 cams and the Focus cams
Intake:
ZX2 (VCT) 214 deg @ 0.050", 0.367" lift
Focus 205 deg @ 0.050, 0.352" lift
Exhaust
ZX2 (VCT) 212 deg @ 0.050", 0.338" lift (exact duration not verified, yet)
Focus 206 deg @ 0.050", 0.343" lift
The VCT advances the exhaust cam 30 crank degrees under certain conditions, including low rpm. This reduces overlap and improves low end torque. VCT also allowed Ford to use longer duration cams in an emissions controlled engine.
If you are building a non-emissions motor the VCT isn't going to help performance (except maybe improve low-mid torque in a road course racing application.)
However, if you need to meet emissions testing, VCT will let you use longer duration cams, especially at lower rpm, before emissions become a problem.
