American race cars (formerly - OT: new car advice)

[Mike Garfias]

Not necessarily.

Are we talking peak flow numbers? Average flow numbers?  Area under the curve?
What about velocity?  I'd rather have a smaller head that has flow numbers
about the same as a larger head (it happens, compare an AFR 205cc LS1 head vs
a ported LS6 head).  The smaller head will have a higher charge velocity,
which fills the cylinder more completely.  That gives you more low end torque,
while not sacraficing high end power.

Port shape/size determines the flow numbers ever bit as much as the valve, and
I would argue that you can't really seperate them.

ALso, I just looked up the flow numbers for a 4v DOHC Ford head (as used on
the 03 cobra).  At .500 lift they flow 266cfm.  An LS6 head flows about 270cfm
at .500.  Seems pretty close to me.  Btw, that is stock for stock comparison.
I've seen C5R heads that flow right about 400cfm ( 800hp anyone?).

Bob Holtzman spoke forth with the blessed manuscript:
> On Tue, 22 Nov 2005, Mike Garfias wrote:
> 
> > Robert N. Eaton spoke forth with the blessed manuscript:
> > > Mike Garfias wrote:
> > > 
> > > >Two small valves weigh more than one single one. 
> > > Not really. Think cube-square law.
> > Yes, really.  you're failing to take into account the weight of the stem.
> > 
> > Two valves = two stems 
> 
> How about thinking weight per flow area? You will still be rev limited but 
> should make more power at the revs available because you're moving more 
> mixture.
> 
> -- 
> Bob Holtzman
> "A man is a man who will fight with a sword,
>  Or tackle Mount Everest in snow;
>  But the bravest of all owns a '34 Ford,
>  Who will try for six thousand in low!"
>                           Roger Huntington
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