Holley EFI System - A Stroke Of Efi Genius

We Test The Hye-Tech Performance 391 Stroker With Holley's New EFI

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Two gaskets are supplied to seal the plenum to the base. Don't use any sealer on them. Just four stainless steel bolts are needed to hold the top down.

The cool thing about tuning an EFI motor is that you do it while the engine is running. Also, the perfect tune-up is usually just a few keystrokes away, but it may take a while to get there if you're not careful. That's because it's just as easy to go way off base with your fuel map as it is to get the thing right in a matter of minutes. Holley has gone to great lengths to supply what it feels will be a reasonable fuel map for each particular EFI kit, but just like with a carburetor, there's always some power to be found with tuning somewhere. However, unlike tuning a carb with traditional jets and air bleeds, tuning EFI takes only seconds, and the results can be felt instantly.

In the end, this stroker Mouse made some great power, and the fact that it idled incredibly smooth at just around 600 rpm points to its being a great daily driver.

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The throttle position sensor (TPS) goes on the side of the throttle body and tells the computer how far the throttle blades are open. This can be roughly translated into how much power your foot wants the engine to make.


JE Pistons
Huntington Beach, CA 92649
Holley Performance Products
Bowling Green, KY 42101
Vrbancic Brothers Racing
Total Seal
Phoenix, AZ
(800) 874-2753
Hye-Tech Performance
La Puente, CA 91746
C.A.T. Power engine parts
Baldwin Park, CA 91706




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