Well I have a crack developing in one of my cast iron collectors.
Was able to source another manifold from a generous member on here, and my friend suggested porting them.
I have ported the heads on my AMC 401 V8 a few months ago and it was pretty easy.
So I was wondering how deep should I go porting the collectors. I have seen people go only a few inches all the way to hog the whole thing out. I am more concerned about not losing any spool then power up top. Faster spool and mid-range is what I am looking for.
My other question is I will be replacing my UP with an STi UP. I have seen people not porting the port that connects to the UP if they are using a stock UP. Is this true?