Been porting my tpis base,slp runners,and plenum.I`m just curious how much being perfectly symmetrical or round the transitions from plenum to runners really matters.I understand a problem of causing turbulence,and stepping up being a problem but what if the shape is slightly changed.Ive seen some done that are perfect with extrude or cnc and mine are not perfect.However,they are gasket matched near perfect as far as not having a step up where the different parts of the intake meet.On a street car does it really make a big difference or am I making a big deal outa nothing?

 

If its gasket matched well shouldnt be a worry, those runners are so long doubt some flaws( im guessing from your grinder) arent going to change a thing.

Short runner intake or inside head port, yes it changes things quickly.