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Herein lies the culprit! The change from flat fiber washer to "O" ring. When the "O" ring is applied to the attachment screw and tightened to the torque spec, the bottom of the fuel bowl is deformed upward. This deformation reduces

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There was a bit more work with the Billet pump package, but it proved not to be the problem. Moving on, OK, not the fuel system. Try running the engine as a normally aspirated engine. Remove the connection between the turbo and airbox. Believe it or

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I removed the entire airbox to to check all the plumbing connections.

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While the airbox was off, I again check all the pressure hoses to the carbs. Oh, what have we here. BIG leaks in the pressure lines to the carb bowls. Two leaks like this. Not observed before because the fittings were tied to that fuel line and the sp

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Pulled all the pressure hose off again and check for leaks and continuity. All OK, no problems at all.

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Next test, connect high pressure port from airbox directly to the "T" into the carb float bowl pressure lines and try a run. Still didn't work. Same smooth up to 4200/4300 RPM, smooth drop to 3200 RPM, smooth acceleration up to 4300 RPM, drop

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Requests to check the fuel delivery system. Started with the gascolator. Any large quantity of crap in the gascolator? Here's the fuel from the gascolator in the test vessel. A tiny bit of black crud from who knows what. But not enough to cause a pro

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Request for fuel pressure input to the fuel pressure regulator. Installed a fuel pressure sensor on the input to the regulator. So now we have differential pressure out of the regulator and pressure into the regulator.

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Run the engine, check the pressures. All seems OK. 5 lbs into the regulator and 3.8 lbs out of the regulator. This is with the Billet mechanical pump. Which became the next source of concern.

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Remove the Billet pump from the circuit. Run with only electric pump. Input line connected directly to the regulator. At the same time, remove airbox pressure from differential gauge to get absolute fuel pressure out of regulator.

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Differential pressure with engine running on electric pump: 3.8 lbs

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Input fuel pressure: 5 lbs. Just like with the Billet pump. Next request was for a fuel flow test. Reconnected the Billet pump to the fuel circult. One electric pump running fuel through the billet pump produced 1 gallon of fuel in a bit less than 3 m

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Here you can see where the gasket was cut by the bowl where it wasn't properly located.

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The issue being the softness and flexibility of the gasket material. Makes it difficult to ensure proper location while reattaching the bowl. The gasket is probably fine for a carb rebuild where you are doing it on the bench and can turn the carb over f

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Next request was for a compression check. 80/80, 80/80, 80/80, 79/80. No problem there. But while doing this I decided to check the plugs. Cylinder #3 plugs looked different. WHY?

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Turn the plugs over and one plug on #3 looks funny. Calls for a closer look...

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Looks like that plug had been bumped some time during transport. Porcelain shows a crack. OK, replaced ALL the plugs. Engine still didn't run right.

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After the engine run still surged, I investigated the seating of the float bowls & gaskets. This one shows how the new gasket wasn't properly located, see arrow.

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Then I removed all the cheep crap connectors (with folded sheet metal pins) provided with the gage package, re-ran all the wiring and replaced the cheep connectors with good, 9-pin, sub-D connectors.

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Mounted the gage and turned on the electric fuel pump. Bingo! A pressure reading. It works now. So now I have a good operating differential pressure gage.