6.0 LS1 Fuel System

[Bill Ford]

I just got my 2004 6.0 motor installed in a '67 Chevy SWB Stepside and I can't find a fuel return fitting on the motor. I see the fuel supply fitting on the drivers side of the intake manifold.

Does this motor have the return incorporated into the fuel filter somewhere between the motor and fuel tank? I've seen a corvette style fuel filter with a return advertised in the S&P catalog.

I also don't see any fuel pressure regulator on the motor. I guess I'll need an aftermarket one - should it be in the supply line or does it need to be in the supply/return loop?

Can someone give me a quick lesson on how the fuel system should be set up on this motor?

[RedHeartbeat]

Buy the Corvette internally regulated filter like on S&P's website. Wix #33737. Fuel setup should be Fuel tank to fuel pump to 33737 filter to fuel rail. Return line goes to fuel tank. The fuel filter will regulate the fuel pressure at 58 lbs. Every filter gives you a new regulator. You'll need (1)5/16 and (2)3/8 quick connects, about $12 each. You can run rubber fuel line if you purchase the line made for fuel injected vehicles, it has a teflon inner liner to handle the extreme pressure.

[Bill Ford]

OK, thanks, Redheartbeat. What do you recommend for a fuel pump? I've heard that an in-tank pump is best but I hear lots of guys talk about externals also. Do you know of a long life external pump?

I know I'm really picking your brain but I have no experience with high pressure fuel systems. I saw on some post the other day that a 2000-02 F-body tank would fit my truck frame and have the pump inside the tank.

[RedHeartbeat]

I'm not sure about the f-body tank fitting in the truck. You could go to a salvage yard and check out what's available. Whatever you get, be sure you get as much of the fuel and return lines as possible. The external fuel pump should be enough to get you going, though I've never used one. Both my conversions were on a 92 and 93 with pumps in the tank from the factory replaced with Walbro 255LPH pumps. The Walbro pumps were designed to replace the pump in a Buick Grand National.

[1BADC10]

I have a buddy of mine that has an LS1 swap recently completed this past weekend. I know he's got a returnless setup. Are you sure you don't have one of those? Just asking...

[Bill Ford]

1BADC10, first you must realize you're dealing with a complete novice but I've read that the reason you need a recirculation circuit in the fuel system is to keep the pump from building up excess pressure all the time. "Running against a wall" is the way it was put.

I think that is the purpose of the filter/recirculator/regulator that RedHeartBeat mentioned. By the way, I have that WIC 33737 coming in today.

RedHeartBeat, my parts man did not know what rubber fuel line you were referring to. All he knew about was the hard plastic type line. That type line requires special tools to push the line onto the barbed fittings. Could you provide a little more info on the line you referred to?

[RedHeartbeat]

The rubber fuel line is available at any Autozone in bulk. It looks like standard old-fashioned fuel line only it is designed for extreme pressures. On the outside of the fuel line it will say that it is for fuel injection use. Standard generic old-fashioned rubber hose will burst with too much fuel pressure. It may not happen right away but it will eventually. Most stores carry the hose in short 18 inch lengths but you'll need a lot more than that, most likely. Just be sure when you tell the person behind the counter that you want fuel hose for a fuel injected application. It will slip over any fitting just like the old rubber hose. Dorman makes the fuel connections that will fit on the fuel filter and fuel rail. You'll need one female 3/8", one female 5/16" quick connect and one male 3/8" for the filter. You'll need one female 3/8" quick connect for the fuel rail. The male connector for the fuel filter, I buy a double ended connector and cut it in half to make two connectors. One goes in the fuel line and filter, the other goes in the drawer of spare parts.

[rosscob]

The fuel rails changed. I don't know exactly which year, but I know they changed. You need the fuel rails from an older vehicle that still has the return fuel line.

[RedHeartbeat]

The only years with a return I believe were 97 and 98 in the Corvette only. All others have a returnless type fuel rail unless they have been modified. I've owned two 98 F-body engines and they both have the returnless fuel rail. The only true benefit is a cooler fuel charge.