Hopefully if i do this right a mod will sticky it for other members to use. I'm currently in the process of swapping my L59 (flex fuel 5.3) to an LQ4 6.0. So far, I've gotten the whole wiring harness disconnected and intake manifold removed. Plan to use the intake manifold and throttle body from the 6.0, fuel rail and injectors front the 5.3 (because of flex fuel). Has gone really well so far. Plan to pull 5.3 out of the truck tomorrow morning and have 6.0 in by tomorrow night. Also using 5.3 wiring harness as my injectors have different connectors than the 6.0 as my original engine has a flex fuel system.
Truck is a 2007 GMC Sierra 1500 Z71 CLASSIC
Post-6.0 swap edits: We ended up pulling the radiator, fans, grille, passenger side wheel and inner fender for ease of removal/installation and the inner fender for accessibility. These engines sit so far into the firewall that its necessary to pull the radiator/fans to get the engine out and back in without fuckin shit up. Also removed the good and intake manifold, as well as the exhaust manifolds because they were easier to take off once the engine was out. My biggest piece of advice would be use WD40 on ANYTHING that you think would be difficult, because it will be. Most of the time spent on this was due to PITA nuts/bolts, a lot of that could be because of the excessive moisture here in WA But either way...
When we were ready to put the 6.0 in, we removed the drivers side exhaust manifold to clear the steering shaft (my engine came from the junkyard complete minus accessories) and from there it was literally just piecing everything back together. Used 5.3 exhaust, throttle body (same P/N on the 6.0 piece anyways) fuel rails and injectors (flex fuel, though I've heard you can use the 6.0 stuff, I went this route for ease of installation/time purposes. I don't run ethanol anyways). The only things I had to change were the oil pressure sender to match the plug I had on my existing harness, and I changed out my starter to the 6.0 (5.3-6.0 starters have different part numbers, starter motor appears to be larger on the 6.0 starter). Truck is running in HP Tuners using the stock 5.3 tune with tr cylinder volume changed for the 6.0.
Overall the swap is really straightforward, just takes time and perseverance to finish, as you'll find more than enough bolts you can only get an 1/8th of a turn on (bell housing bolts....) but it is SO worth the time if you have a 4.8-5.3.
Truck is a 2007 GMC Sierra 1500 Z71 CLASSIC
Post-6.0 swap edits: We ended up pulling the radiator, fans, grille, passenger side wheel and inner fender for ease of removal/installation and the inner fender for accessibility. These engines sit so far into the firewall that its necessary to pull the radiator/fans to get the engine out and back in without fuckin shit up. Also removed the good and intake manifold, as well as the exhaust manifolds because they were easier to take off once the engine was out. My biggest piece of advice would be use WD40 on ANYTHING that you think would be difficult, because it will be. Most of the time spent on this was due to PITA nuts/bolts, a lot of that could be because of the excessive moisture here in WA But either way...
When we were ready to put the 6.0 in, we removed the drivers side exhaust manifold to clear the steering shaft (my engine came from the junkyard complete minus accessories) and from there it was literally just piecing everything back together. Used 5.3 exhaust, throttle body (same P/N on the 6.0 piece anyways) fuel rails and injectors (flex fuel, though I've heard you can use the 6.0 stuff, I went this route for ease of installation/time purposes. I don't run ethanol anyways). The only things I had to change were the oil pressure sender to match the plug I had on my existing harness, and I changed out my starter to the 6.0 (5.3-6.0 starters have different part numbers, starter motor appears to be larger on the 6.0 starter). Truck is running in HP Tuners using the stock 5.3 tune with tr cylinder volume changed for the 6.0.
Overall the swap is really straightforward, just takes time and perseverance to finish, as you'll find more than enough bolts you can only get an 1/8th of a turn on (bell housing bolts....) but it is SO worth the time if you have a 4.8-5.3.
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