DeTomaso Mailing List: March 2000, Message #6

FWIW, I've talked to an Australian head porter who claims the 2.19" valve 
is too large.  The smaller 2.05" stock valve gives you more distance to 
make the short side turn.   He claims flows up to 285 CFM, IIRC.  
Your numbers are similar to others I've seen.

Dan Jones

> I have a question regarding 2v aussie heads. I have a set I am working on
> now 
> trying to get some decent air out of them. They have 2.19 valves with
> basic 
> pocket porting and went 212@.500 lift like that. I noticed when flowing
> them 
> that started tomake a "shrill" sound at approx .350-.400 lift. I believe
> this 
> was the air shearing off of the short side turn. I then brought the short 
> side turn back in stages to where I was in danger of hitting water and got
> 
> 252CFM. I know the short turn is the key here but can't go any farther.
>  Has anyone ever filled in the floor of this port staight back from the
> short 
> turn? My thought was that it may give the air more of a chance to "drop
> over" 
> this still abrupt short turn and pick up flow. There is still plenty of
> port 
> area even in a 2v head. Right now untouched they have 2.44 sq. inches of 
> critical area. According to the PLPA formula this port should be good to
> 7600 
> rpm on a 351 purely in terms of area. Maybe this could reduce port volume,
> 
> pick up velocity, and increase flow? Should be done testing this in a
> couple 
> of weeks if anyone is interested in the results. Any ideas would be
> greatly 
> appreciated. Thanks
> 
> Neil Erickson
>