Jerry Hey wrote:

I have started construction of the intake manifold.  Step one was to
trim the 180 sweep which came with one 18 inch leg and one 8 inch leg.
  I started by trimming the leg that will butt up to the throttle body
as short as possible.  Keeping the sweep close to the engine  is
critical to it fitting under the cowl.

    Secondly, the over the top leg was trimmed  so that it will  just
reach the plenum.   Depending on bell mouth tube stick out, the top leg
will  have to be trimmed a little more.  As it is,  the entire intake
tube was cut down to a single 16 inch piece.  Added to this is the
length of the throttle body from the trochoide face to the outboard end
  which was 4.25 inches.
As seen in the photos the intake length is 20.25 inches:  a little
short for the 6000 rpm engine and a little long for the 7500 rpm
engine, but adjustable either way.  If  you wanted to have a perfectly
tuned   engine for any rpm  between 5000 and 7500 , an adjustable
intake between 18 and 22 inches would do the trick.  In my case (2:17
drive),  I am going to tune for 6000 rpm and not worry about it for
lower rpms.  The 6000 rpm length is 21.65 inches which can be achieved
by  extending  the bell mouths into the plenum about 1.5 inche.
Jerry

 
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