Cylinder head modification can net some serious performance gains. However, once the valve centerlines have been moved, you sometimes have to bend or cut stock guide plates in order to compensate. To solve this common dilemma with aftermarket heads, COMP Cams developed Two-Piece Adjustable Guide Plates for high performance Big Block Chevy engine applications. Created from precision die-stamped and heat-treated steel material for a closer setting and improved durability, these fully adjustable guide plates feature an interlocking design that enables a reliable and true adjustment in the one axis needed for most valves. This prevents issues associated with prying or cutting the guide plate, which often make it difficult to line up prior to welding.