The Porsche 356 was equipped with a similar rocker shaft as this high lift rocker arm shafts, so you see again that many parts that you think the brand is often copied from a properly functioning existing part. These tumblers have a ratio other than the original 1.1 to 1 ratio, ie 1.25 to 1 or 1.40 to1. InUnlike the original tumblers are equipped with this bowl-shaped line bolts, resting perfectly on the tappets at all times. The rockers are made ​​of forged chrome-molybdenum and are journalled with bronze bushings, a vast improvement on the needle-bearing specimens which were used previously to this is the friction reduced to a minimum. Also, the rocker arm shaft with oil passages so that all moving parts are lubricated, continuous use rocker adjusting plates (not included, see options) for coarse adjustment after you finely adjust the rockers with the adjusting screws. This is necessary in order not to close it. The oil channel in the adjusting screws off Adjusting the valve clearance is done on the side of the tappets while the clearance equal to original between the valve and the rocker arm is measured. The supplied mounting rocker studs are made ​​of chromium molybdenum and run wider for a stronger connection. This tumbler sets withstand high valve spring pressure, high speeds and are the strongest on the market. Are pair comes with all necessary fasteners. Applicable to the following engines: Type 1 engines since 8/1965 and later type 3 engines all years CT / CZ engines all years WBX engines all years