Id stick to the cvh . Dont forget torque wins races bhp wins engines, a cvh is gonna rev and pull harder with all the punch you want where as zetec would probably rev smoother and maybe that bit slower.
TBH lately there seems like u can create similar engine power with both setups ,down to the individual . A strong cvh tho will require steel components in reality which may cost more than a standardish zetec block as these are a bit stronger in o.e form.