I have built a very strong CVH.

The problem is with any zetec based engine is the long stroke which creates a lot of low down torque meaning that when the turbo comes on boost, you get a sudden torque spike. This is not good for traction. Plus the fact that over a certain rpm, the power begins to drop off (usually 5krpm). Due to the angle of the rods that the long stroke creates, it also loads up the bore thrust face and promotes piston and bore wear. This can all be rectified by having a set of rods and a crank machined to reduce the stroke.

My CVH comes on boost at 3k and starts pulling. At 4k rpm it starts to pull stronger and by 5 k it's really pulling hard. This progressive delivery of power helps traction and your gearbox to stayin one peice (no sudden surge of power). It may not feel as fast as the boost comes in but the bonus will be that you actually have grip and start going somewhere.

Also, I have fitted a Stage 2 Plus gearbox with ATB diff from The Gearbox man just to help issues around broken gearboxes...