oldsmobile joe

Royal Smart Person
Nov 12, 2015
Look what finally showed up today... Holley EFI in-tank fuel pump #12-306. I've been waiting over 3 months for this. Installs inside my stock fuel tank, requires no external regulator, and no return line. Happy to have it!


• This in-tank fuel pump module is a high-pressure unit that flows 255 liters per hour (LPH) and is capable of supporting electronic fuel injection (EFI) engines producing up to 550 horsepower • A pre-calibrated fuel-level sending unit designed to work with the factory fuel gauge for this application is included • This module also features a HydraMat filter which has a unique internal reservoir that keeps fuel available at the pick-up and also provides protection from contaminates Fuel pressure is internally regulated to 58 psi eliminating the added expense and effort of purchasing and installing an external fuel pressure regulator - no separate return line is required because this module returns excess fuel right inside the tank! This 1978-87 G-body Muscle Car EFI Fuel Pump module was designed as a direct replacement for your factory pick-up and sending unit. There is no need to purchase a custom EFI fuel tank. You can even retain the factory fuel hard line - just connect the outlet of the pump module to the hard line on your vehicle with EFI-rated fuel hose and hose clamps available in the Earls Vapor Guard line. This Muscle Car EFI Module includes a 255 LPH fuel pump and a Holley HydraMat. HydraMat is an amazing patent-pending fuel reservoir system that reduces fuel starvation issues that might otherwise occur while cornering, accelerating, stopping, traversing inclines, and during low fuel conditions.

View attachment 181405
please report back to us on this item. can't wait to see it in action.


Supporting Member
Apr 3, 2015
Spring, Texas
What are you going to run for a fuel gauge James? We used a stock style efi tank (Spectra - un-baffled except for a tray in the bottom to pick up fuel). We used an aftermarket fuel gauge. Fuel slosh shows on the gauge with the needle bouncing around. We installed a capacitor in the wiring for the gauge at the recommendation of the manufacturer and that helped dampen it but didn't make it go away completely. I'm told the O.E. gauges have further dampening built into them so you don't see as much needle movement due to the fuel sloshing around.

The car runs fine and it's a minor nuisance. Just check the fuel level when you crank the car up and the fuel isn't sloshing. Also at highway cruise the needle settles down substantially. Just ignore the gauge while you are in stop and go driving.

Just thought I would run that one by you. If we had it to do over, we'd run a tank with more baffling.
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