Outlined below is a detailed, step-by-step process that every Jaguar cylinder head and Land Rover Cylinder head sent to Coventry West to be rebuilt undergoes. Coventry West cylinder heads are extremely high quality units that come with a 12 month, unlimited mileage warranty.Head is stripped down to nothing, no studs, spring seats, nothing.Head is steam cleaned, dried and bead blasted. Then blown out, steam cleaned again, blown out and ultra sonic cleaned.Head is pressure tested under water at 30-40 PSI to check for leaks from cracks or corrosion.All threaded holes are chased and heli coiled if necessary. This includes spark plug holes.All Tappet guides are checked for clearance and integrity of fit and locked down. All 12!!Valve guides are replaced as necessary. Early intake guides are replaced even if not worn to allow inlet valve stem seals.Seats are cut to a three angle cut.Valves are hand lapped in to insure a good seal and to also check for fit on the valve seat.Cams are polished and checked for pits and worn lobes. Later style cams are available. We thread the ends for the tach pickup if the later cams are used on a early head. Valve clearances are properly adjusted and the cams set at TDC. Heads are painted (actually before this point) proper color for the car or to the customers preference. Heads are hard foam packed in a double corrogated box. This has passed a test from UPS with a 20 foot drop without damage. The box and foam is reuseable to return your core if you bought a head from our stock.