The process involves chemical cleaning, a full strip down of the head, pressure test, full decoke, valves polished, valve seats refaced then reassembly and quality checked.�50 will be refunded upon receipt of a fully functional / usable cylinder head (inc valves, springs and collets).Rocker shaft not included, but available at an additional cost.Suitable for both the Phase I & II Renault 5 GT Turbo.