Sidewinder vs PI intake .....

[pbf777]

      Well, I do understand, but being one who also has been porting cylinder heads, intakes, and even blocks (Flat-Heads and even lawn mowers!     ) for several decades, and yeah, we have had a SF-600 for that long too!  (    )  I have come to realize that even when I attempt to explain what's needed in the way of port-work to better something, most potential customers remain as such, because they just don't understand, and god forbid should they attempt such and they most often realize, the job just ain't for them!  I'm not sure if there are any real "secrets"; it's more like looking at a masterpiece painting on the wall in the museum or gallery, and no matter how hard one stares at it, or the techniques involved or explained, if uninitiated with the process and intent and possess the talent for it, your just not going to go home and be able to duplicate the artistry.   
   
      I was just curious of what you had determined.   

      And, just of note, I find it particularly interesting in the individual intake manifold port flow study to be sure to attach the intake manifold to the cylinder head flow testing the entire inlet tract and realizing the effect one has on the other, as often this proves to be something different than the values of each individually!   

      Scott.

[Joe-JDC]

I often flow heads with the manifold, especially if I port both for a customer.  I always flow my intakes with the head they are going on.  I also bolt the carb on with butterflies wired open on some combinations, along with sometimes mounting the head on the flow bench with exhaust facing out so I can flow the exhaust through the actual header used on the engine.  I have even flowed exhaust manifolds that I have ported for folks in years gone by.  Leave no flow path question to doubt when it comes down to finding what works and what is theory.  It really gets interesting when you flow different size carburetors on a manifold through the head with valve at camshaft lift. I sometimes even flow a port with the valve stem only just to see how much the valve job is affecting flow, or the valve is shrouded.  If you can think of it, I probably have tried it at some point over the years.    Joe-JDC

[JC-427Stroker]

Great post.

[pbf777]

  I also bolt the carb on with butterflies wired open on some combinations,..............   

     And even set the throttle butterflies at part throttle values, say 45° vs. 90° +/- , and watch what happens!       This can have some value in understanding for part & transitional throttle mismanagement particularly of fuel with carburetors, but more so for individual runner fuel supply fuel injection its' turns into an air supply effect.     

    Scott.