Center Bolt Pattern Measurement
Due to the confusing W2 cylinder head part no. / casting no. variations, use the following measurements to
determine which header will fit your application.
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If the center bolt hole pattern spread measures 3-15/16” from the center of the left bolt hole to the center of the right bolt hole; you must use TTI's 1-3/4" W2 "STEP" Header.
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If the center bolt hole pattern spread measures 4-3/4” from the center of the left bolt hole to the center of the right bolt hole; you must use TTI's 1-7/8” W2 Header.
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Dual Bolt Pattern Heads: Either header may be used.
