What are you guys doing for fuel systems on your efi LS conversions?

If you are staying at stock HP levels return-less is fine.

If you are adding any boost or plan to swap the injectors because of heads, cam, or whatever, it's best to swap to return.

Return-less in my opinion can get airlocked and can be hard to bleed. Boost returnless is a no go in my opinion as your injectors have to be huge and the differential pressure gets low so the flow rates crater.

It's my understanding that many factory returnless setups also have PWM pumps to reduce current in low flow demand situations.

gnvair said:

I know 99-up is return less.

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04ish and up are returnless......but that doesn't help you as I don't believe 99-03ish gen3 return fuel rails are compatible with a gen 4 intake.

When I did my 6.0 swap I went with the Holley in tank setup and wix frame filter. I'm just running a stock bottom end, heads/cam/ headers and terminator xmax and it has worked flawlessly for my setup. 435 at the tires with a 4L80. stays between 58 and 60PSI at the rail.

gnvair said:

Is that the internally regulated filter like the Corvettes used?

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No, I had that one as well, but realized i had the return line running back into the vent line in the Holley drop in pump. So I redid it with a standard LS Wix fuel filter. The Holley pump module already has a pressure regulator built in set to 58PSI.

gnvair said:

Does the Holley pump module fit the stock tank? I'm curious to see what that looks like

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This is the one i am using. It went right into the stock location, hooked up the fuel gauge wire, grounded it and supplied it 12v from the relay block I installed.

Also an FYI-

A local guy who does LS swaps for a living that I know pretty good has had a recent rash of poor performing vette filter/regulators. GM and WIX through multiple suppliers. Online appears to have some counterfeit or quality rejects as he had multiples go bad in a shot. Ended up getting a good one at the dealer but at the cost of mid $100.

The vette filter/regulator used to be a good budget option but it appears the budget has disappeared, especially when you need the quick coupling fittings.

81cutlass said:

Also an FYI-

A local guy who does LS swaps for a living that I know pretty good has had a recent rash of poor performing vette filter/regulators. GM and WIX through multiple suppliers. Online appears to have some counterfeit or quality rejects as he had multiples go bad in a shot. Ended up getting a good one at the dealer but at the cost of mid $100.

The vette filter/regulator used to be a good budget option but it appears the budget has disappeared, especially when you need the quick coupling fittings.

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This is true. Mine has been really good to me.
It was a Wix, I had ran it with a walbro 255. Mine ran a little high at 63 ish psi. That said I lot of people I know have had issues with newer ones, even Wix branded.

Not sure if someone posted it since I have read the whole thread. Holley have their own version of a filter/regulator deal. Kinda pricey but keeps that simplicity.