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Thread: So how much porting is too much?

  1. #1
    Advanced Tuner CatnipG5Bandit's Avatar
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    So how much porting is too much?

    I'm currently porting a spare 2.2 head for my supercharger build. I measured the intake ports at 155 or 160cc. I'm currently knocking on 180cc just getting rid of the casting flash and foam look, and also knife-edging the divider. Should I go any farther than that? These ports are already bigger than my stock sbc heads.
    2008 Pontiac G5 2.2L (main oil seal became a crunchy Autumn leaf, RIP)
    2016 Fiesta 1.0L Ecoboost - Project "not-so-detestable"

  2. #2
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    The true answer would be a flow bench.

  3. #3
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    These heads do not need much on either side, as far as I understand. I have always been told to just clean up the casting flash and knife edge the divider, like you did. I would have had it flowed before and after though, just to make sure the changes actually helped.

  4. #4
    Senior Tuner cobaltssoverbooster's Avatar
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    the only way to guarantee these ports do not die is to monitor the flow ratio and measure the the velocity with an air probe on the flow bench. its very easy to ruin these even with a standard flow bench.
    Yes ive destroyed a set.
    2000 Ford Mustang - Top Sportsman

  5. #5
    Advanced Tuner CatnipG5Bandit's Avatar
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    Thanks for the input guys. I don't see a huge amount of harm getting rid of the casting flash (which was quite a bit on this head) and knife-edging it. I did cut myself on the knife-edge though. In theory as long as I'm not changing the port shape I should be fine. Right? I have been tempted to build a flow bench though...
    2008 Pontiac G5 2.2L (main oil seal became a crunchy Autumn leaf, RIP)
    2016 Fiesta 1.0L Ecoboost - Project "not-so-detestable"

  6. #6
    Senior Tuner cobaltssoverbooster's Avatar
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    dont grind the nubs off the top of the intake runner. thats extra meat left by the factory to keep lifters from pushing through. if gm decided it was required for stock spring pressure you better bet you want most of it there when you go high spring pressure.

    on the intake side push both valves open to .350" and turn a vacuum on the chamber of the head to flow air through. hold a piece of string in the inlet and try to balance it on the divider between the valves. if it is biased to one side work the divider a small amount until it evens out. remove the casting flash and call it good.
    2000 Ford Mustang - Top Sportsman