- Jul 7, 2005
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There are reasons for the different part numbers from MSD. Each part number you were looking at comes with a different spark plug boot end as they come in 90*, 120*, 180*, and Multi-angle. You buy them based on your needs, since many like the 90* to gain additional room for headers especially on GT40P heads. For a stock stock/look spark plug boots are 120*, so when you are looking for wires look at the ends they come with.