LS fuel lines

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Leeztruk

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I'm about to do an LS swap (5.3L) into my '89 Cheyene, which has a 5.0L TBI engine. The throttle body has the factory braided fuel lines. Will these lines support the higher fuel pressure for the 5.3 fuel rails, or should I just make new lines to connect to the existing hard lines that run under the truck? Thanks
 

Schurkey

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The advanced age of that hose and the fact that the OEM pressure was intended to be not more than 13 psi leads me to think you should be looking for new and better.

For that matter, you might want to verify the metal tubing, too.
 

Leeztruk

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Thanks, Shurkey. Was hoping to escape the fuel line dilemma by using what appeared to be a factory "gift" that could be adapted to my fuel rails.
 

MrPink

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There are plenty of companies that make new lines that are bent just like OEM. They should hold the pressure, but I'd personally run AN fittings and lines.


I am actually running AN fittings and lines on my current TBI setup but I am also going to be going LS. I built my fuel system to already handle it. I have an EP381 Delco pump in tank, -6AN fittings from tank to TBI, a really nice Holley ADJ FPR with-in that setup also, because I have it regulated down to TBI pressure currently from the 58-60psi the the EP381 puts out.
 

Schurkey

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I'd personally run AN fittings and lines.
It's crazy to use hose when metal or OEM-style plastic tubing will suffice.

Hose has a shorter service life, is more porous, weighs more, and is far more expensive than double-wall seamless steel tubing.

"AN" hardware sold by most online retailers is NOT actually "AN" spec. "AN" is a long-obsolete military-grade specification; what Summit and Jegs sells is industrial-grade not military/aerospace grade. (Deceptive advertising)

I have an EP381 Delco pump in tank, -6AN fittings from tank to TBI, a really nice Holley ADJ FPR with-in that setup also, because I have it regulated down to TBI pressure currently from the 58-60psi the the EP381 puts out.
When I replaced the pump in my '88 K1500, I used what was then supposedly the "hot tip", the EP241 pump. There's no need for an external regulator because the OEM TBI regulator is perfectly capable of maintaining the 9--13 psi spec'ed for the TBI system even when used with a so-called "high pressure" fuel pump. As long as the return side of the system is adequate, the pump only produces the pressure the regulator allows.
 

Leeztruk

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Before I got the '89 Cheyene, I had a '80 C10 with a 5.3L . In that truck I built my fuel system using Dorman nylon fuel line and fittings. For the 5 yrs. that I drove it, never had an issue with leaks or fittings popping of their nipples. Was hoping to avoid having to do the same with this truck
 

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