View single post by 907 heaven
 Posted: 04-07-2010 11:37 am
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907 heaven

 

Joined: 03-10-2010
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  I don't ever really do so little work as that, so can't honestly say, but what I can say though is that in terms of "bang for buck" - you need to be working at the valve end of the port.  The shape of the valve head, valve seat and short side turn of the port influeneces flow more than anything else.  Many people look at a head without the valves in and forget that the biggest restriction is the valve itself - "porting" is perhaps not the best term to use - since the actual port is not really that much of a restriction - of course it can be improved; but the part of the port that really matters is the 3/4" immediately before the valve.

Matching the port and the intake manifold is good practice and won't hurt, but I would really not expect to see a significant gain in airflow to be honest.

My advice would be to just simply smooth out the lumps and bumps on the short side turn of the port (don't go wild), put a 30 degree back cut above the seat (on the valve) and cut a 3 angle valve seat on the intake port.  Trying to describe porting is very difficult; but what I've described above will get you a reasonable improvement without a lot of work.

Regards 

GARRY