I just finished installing a Hahn stage II this weekend and noticed that the ports on the manifold were much smaller than my Patriot ported head ports and the manifold seemed smaller even than the stock head ports (though didn't have it with me to compare).

Is this intentional for velocity or some reason or would my setup benefit from a port-match?? ...seems to me that it would cause turbulence in the exhaust port and rob power...?


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2002 LS Sport coupe

I noticed they were small too, but they did match up to the stock head. I would say port match them to your new head, thats what I'm going to do when I get mine done.

yeah you want the exhaust manifold port to be a little bit bigger than the port in the head actually (or so i have read), because having a step there helps to prevent exhaust reversion.




Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said

They are smaller than the head ports. Open up the manifold some, there's plenty of room to do it. I've done it BTW and no ill effects. Did it on the factory head then for the Patriot head too.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

thanks...didn't know if there was a difference with turbo, knew about the step for a n/a header

did anyone do this after it was already on? notice any gains or quicker spool-up?


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2002 LS Sport coupe