4.3 to 5.3 ls swap
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Registered User
Joined: May 2023
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4.3 to 5.3 ls swap I have a 2007 chevy 4.3 and I'm putting a 02 5.3 into it and I trying to figure out what I need to do about the fuel system if I can use the factory pump or if I need to change it out. Thanks in advance
TECH Apprentice
Joined: Aug 2018
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Did the 4.3 retain return-style fuel system into the GMT 900? Or is this the GMT800 classic?
I did a 99 Silverado ecsb 2wd 4.3 to 5.3/4L80e swap. It's a great combination. Just source an engine wiring harnesses from a 03+ as the 99-02 are different and not compatible with the later ones. The fuel pumps are the same. I think in 2004 or so is when they switched to return less. I'm not sure on the V6.
I did a 99 Silverado ecsb 2wd 4.3 to 5.3/4L80e swap. It's a great combination. Just source an engine wiring harnesses from a 03+ as the 99-02 are different and not compatible with the later ones. The fuel pumps are the same. I think in 2004 or so is when they switched to return less. I'm not sure on the V6.
TECH Fanatic
Joined: Jan 2018
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From: Dade City, Fl.
I think 2006 there was a change over at some point for returnless fuel system. Some 2006 4.3's had a fuel pressure regulator and others had a fuel pressure damper. The regulator being used in the return style system
