The Ultimate Guide to EFI, Part 4 – getting fuel into your engine the correct way

Generally, when talking about rebuilding cars we break them down into several large chunks, including: engine, paint & body, suspension & brakes, drivetrain, and interior.

But cars are actually several thousand tiny jobs loosely grouped together, but also intertwined. I can’t finish off the cooling system until I have my crank pulley back on, which requires machining for the EFI system. See?

So, while I’d had my intake manifold drilled and welded to suit the 8 LS3 injectors I was going to run, I still had to sort out mounting the custom 8AN (-8) fuel rails I’d been supplied. I’d really preferred to go with 6AN (-6) as that would fit the rest of my fuel system but I figure I can always upgrade the rest of that system later on.

On top of mounting the rails I also had to tap threads into them so I could install fittings to connect up my fuel system. So I had to buy taps. And beer… because this was turning into a bigger job than I’d given proper consideration to…


I recommend buying a really high-quality tap and die set if you’re going to undertake automotive work at any time. The frustration saved using great quality tools is worth the spend alone, though this 125-piece tap and die set from Sydney Tools was only $115 so I’d consider that cheap (though I had to buy the 125-piece kit as it was the only one that had the one tap I needed!)


The key to successfully tapping threads in metal is to use good quality taps, go slowly, and use a cutting spray to help keep the taps in good shape when cutting new threads in.


I tested the Raceworks AN8-to-AN6 adapters and they screwed straight in. I have a very simple fuel system but have still spent well over $1000 just in fittings, from the fuel tank to the engine!


For a break I decided to paint the intake manifold in a matching blue to the rest of the engine. This is probably going to clash against the green paint job but should look good in the gloss black engine bay. I also wanted it to look more OEM than having a green or gold engine.


I then got on with the job of mounting the rails. Initially I’d tried to bend up the 1mm-thick aluminium strap to sit on the inside of the rails so the brackets would almost appear hidden. Unfortunately my fabrication skills suck so I resorted to the simpler brackets you see below.


I test fitted it all and was fairly happy with how I thought the finished product would look. I decided to get the rails and brackets powdercoated black so they’re far more durable and hopefully they almost disappear.


I have used Raceworks fittings on my fuel system as they’re cheap but seem to be good quality. I feed my rails from a 6mm (3/8″) line, which steps up into the AN8 (-8) fuel rails. I made sure to use the proper aluminium spanners when constructing this hose and, as I plan on using E85 ethanol fuels in the future, I have used 200-series Teflon-coated lines and fittings.


I had my intake manifold customised to fit fuel injectors and, after finally mounting them, I had the rails and brackets powdercoated by United Speed Shop in Newcastle. For a semi-OE/stealth finish I chose Oxytech Wet Black.


Ready to fit to the car just as soon as I source a coolant temp sensor. I will use a modern LS-style sensor as it will work with the Haltech ECU.


Eagle eyes will spot the large round sensor on the throttle body in the below picture. That has now been replaced as my Haltech Elite 950 ECU can’t run that GM stepper motor-style idle air control valve (IACV). I am replacing it with a simpler two-wire unit from a Ford, which will be remote-mounted somewhere out of sight (probably near the LS1 coilpacks I am also moving to).


I made up the blanking plate (below) out of 3mm aluminium in 5 minutes just to seal that port up. I will run it on the bench grinder to whizz it a bit neater, then hit it with some satin black to match the throttle bodies before I put it on the car.


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