Musings on Vacuum gauges and fuel pressure gauges

[SJ]

Denis brought up some interesting points in his troubleshooting research.

I was wondering where/how he hooked up the vacuum gauge to the intake
manifold. Besides drilling and tapping a threaded hole in the manifold, does
anyone have a better idea? Is there a vacuum port on the side or underside
of the manifold that can be exploited for this task?

Regarding the fuel pressure testing.
Where can you get the special fittings needed to attach the fuel pressure
gauge to the fuel lines?
I already have a fuel pressure tester, but not the special fittings.

Another thought on fuel flow and pressure testing.
In the audi CIS system, not only is fuel pressure important, but so is fuel
flow.

I was thinking of using a flow meter in conjunction with pressure testing.
The flow meter would consist of a vertical clear tube with a ball inside.
The ball would be non floating, and be smaller in diameter than the inside
diameter of the tube.
To use, you connect the tube in series with the fuel line. Stand the tube
vertically. The gas pushing against the ball and streaming past the ball in
the tube will lift the ball indicating fuel flow.

The tube can be calibrated beforehand by measuring  the time it takes for a
certain amount of fuel to flow thru the tube. Appropriate markings can be
added to the outside of the tube.

Anyone have ideas about what kind of tubing to use and what to use for the
ball?

SJ
85 Dodge PU, D-250, 318, auto
85 Audi 4k - - sold but still on the road
88 Audi 5kq
90 Audi 100q