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Port size for a 3.2ss
I am planning my engine build and wanted some advice on what size ports I should run.
It will be(so far) 3.0 case and crank 3.2 cylinders bored to 98 JE 9.5:1 pistons DC40-mod's' cams Webers headers single plug Heads are currently later 34 intake with 35 ex. ports. I want to open them up some, but don't know har far to go.
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Donnie Currently Porsche-less..... ![]() |
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I would rather be driving
Join Date: Apr 2000
Location: Austin, TX
Posts: 9,108
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Open them up to the early SC size - 39mm This will put your port velocity at the peak range of around 105 m/sec at 7100 rpm (peak HP for Mod_s). Anything much faster than 100 m/sec will not flow enough and you want to maximize port velocity. Also, larger port sizes will be restricted by the carbs on top. I recall you are using weber 40s. Don't forget to match the carb manifolds to the heads.
thanks to John Leutjen for this velocity calculations.
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