Hi guys, I'm a new member, though I've been looking at the forums for a while. I have some questions regarding an engine swap for my 2004 Yukon XL w/ a 5.3 . I want you all to know I have researched this! Lol, I just never find a thread that quite fits my situation, Usually the OP doesn't provide enough info, or it's a much newer engine in a older vehicle yada, yada. (BTW you can thank them for this plethra of over information) I'm not a top notch mechanic so I don't want to get *** deep in a project I can't get out of. I have been recently researching to upgrade my engine (212k miles) something I can work on before she goes bad, although she's fine now. I started looking at reman bottom ends, with the idea of installing a mild cam and having my heads worked. This I am comfortable with, but never one to half *** anything I started looking at upgrades for exhaust, intake, etc.. I realized that for the cost to power ratio I was better off getting a reman 5.3 to 5.7 about 1k more but more power gains with less work. Then the machine shop manager said something that didnt click till after i hung up. "Basically you'll Corvette bottom end with a shorter stroke" You all know where I went from there I can get a complete LS1 or LS6 Vette engine both 2003 neither over 80k on them for the same price nearly as doing the aforementioned . Where will my challenges lie? My current engine (VIN Z Flex Fuel which I don't use) Transmission is a newly remanufactured 4L60E. Sooooo... wiring, ecm, motor mounts, accessories (water pump, alt etc), If there's anything I left out please let me know I can get it. Oh 1 more thing not that it matters as I will make changes as needed, but I run dual alternators a 145 and 270 amp. Would that custom bracket be usable? Thanks in advance folks, and sorry if I missed that exact matching thread.

 

Get a lq4 or lq9 6.0 mild cam heads intake full exhaust. Same amount of money as the ls6 get more power with a 6 0

 

It will all be plug and play but like mentioned above you would be better off finding an LQ9 out of an Escalade, probably will be significantly cheaper than an LS1/LS6, only downside is the LQ9 is an iron block and weighs a bit more but the extra cubic inches will more than make up for it

 

Good place to start with something like this is what are your goals out of this project and what is your budget?

 

Lq4 and lq9 are truck motors. All truck motors from 99-06 GEN3 all plug and play. Gen 4 motors are not 7.5-13

 

I will start looking into the LQ9 options, as far as goals, im not looking to race, just better performance. I carry an extra 1500lbs because of my audio system. I want to have some umph again when I hit the throttle.

 

this is correct, literally any block/heads that has a 24 tooth crank like mentioned above will drop right in. I would have the tune checked afterwards to be on the safe side. Headers will gain power with any of them so consider doing that.

 

Hello all, I have a quick question on the info mentioned above about Gen 3 motors are interchangeable. I have a 02 GMC Yukon XL with a L59 (z flex fuel) motor and 185k miles. The motor is shot, leaking oil, under-powered and noisy. With the vast knowledge in this forum is there another motor I can replace without any mods or replacement of parts? L59 (285hp) fits 02-03 and L59s (295hp) fits 04-07 will this work? or can anyone recommend a motor that will use the same computer, mounting brackets and transmission currently installed. All I want to do is replace the engine, thanks in advance.

 

Either would drop right in.

You could also find a L33 if you wanted to as well.

 

You can use any 99-03 5.3 without changing anything else. The 04+ has a different oil pressure sensor and slightly different cam I believe (not enough to mention really). If oil pressure isnt an issue you can use any 04-06 as well as long as you reuse your current intake/injectors/tb.