• C5 Performance Intake-Exhaust Calculator

    Please answer the questions as accurately as possible. Although the header index number cannot be used directly in our math formulas, it shows you the relationship between engine size, rpm, and how that changes the final product. ***Our C5 header index is for naturally aspirated engines only.***
  • The C5 header index is a numeric reference guide for us to quickly size your header compared to a known standard (usually the stock manifold). 

    How would you potentially use this number?


    If you increased your engine size and wondering if your existing manifold/header would still work, you could run the numbers to compare Index numbers. 

    If the Index number shifts greater than 0.5 you will see a noticeable change in peak torque rpm. Larger Index number = higher peak torque rpm.

    We hope this provides you with a better understanding of how a change in engine size or target rpm affects the intake/exhaust math.  

    We are creating an online quote that will be used to simplify orders. Until then, please contact us via

    email (paul@c5ignitions.com)

    call 920-403-0555

    text 920-810-0946

    weekdays 9am-6pm

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