Cams should (theoreticaly) work regardless of lifter type.
But thats not always the case.
Thats why manufacturers specify what lifter their cam works best with.
The Zex representative I spoke to (over a year ago) said they were designed for the Focus and Cougar with mechanical lifters.
The Zex cams are meant to use the stock valve train components and do not require lash adjustments.
So due to the self adjusting nature of hydraulic lifters they will not work properly.
My advice; stick with what the manufacturer specifies.
