The oil pump housing must be centered on the crankshaft on Gen V V6 and V8 engines to ensure proper oil pump performance. Improper alignment of the housing will affect the oil pressure and can lead to less than designed engine performance or engine damage. GM-51267 is mounted to the front of the block before the oil pump is removed to determine the installed position of the oil pump. Once GM-51267 is fastened to the block, the oil pump can be located and removed, and GM-51267 remains in position. During installation, the oil pump is seated against GM-51267, and then its fasteners are tightened to hold it in its original position. On V6 engines, GM-51267 is also used to align the LOMA (AFM) or engine valley cover (non-AFM) to the timing cover surface, to prevent oil leaks and ensure the AFM system works as designed. Failure to use GM-51267 can lead to oil pressure and flow issues, and result in engine damage or require an oil pump replacement.