What is a direct swap for my 08 5.3 LMG?

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ValleyTahoe

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My 5.3 has 90k and is doing well but just doesnt have the power I'm looking for with 35in tires and 7.5 lift. I'm going to regear soon which will help but I'd also like to get a cheap direct swap junkyard motor and build on the side. I'd like to build the engine a little maybe heads cam and rods etc.


What is the easiest and best swap?
 

Marky Dissod

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With 4L60E, 4.30 or 4.56, because of the 35" tall tires. With 6L80E, 3.73 or 4.10.

ANY Gen4 6.0L or 6.2L will fit in there like it should have been there in the 1st place.
Should also be compatible with whatever engine controller your engine uses.
Perfect opportunity to do a VVT delete if necessary, as well as to delete engine half@$$.

I myself am looking for a 6.0L, preferably aluminum block to lose 100lb off the nose.
I'll need to do more work to make a Gen4 V8 compatible with a Gen3.
 

Marky Dissod

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Even with an engine swap, you are going to see the best performance gain from a set of gears.
Throw some 4.56 in the front and rear and then see how the rig feels.
Everyone forgets that CAFE MpG scores pretty much force GM to undergear these heavy bricks.
I'd think more assertive axle(s) gearing would be both cheaper and more cost-effective than a bigger engine.

That said, if you've money & time for an engine swap, don't settle for anything less than an aluminum 6.0L.
 

Mudsport96

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Everyone forgets that CAFE MpG scores pretty much force GM to undergear these heavy bricks.
I'd think more assertive axle(s) gearing would be both cheaper and more cost-effective than a bigger engine.

That said, if you've money & time for an engine swap, don't settle for anything less than an aluminum 6.0L.
I wholeheartedly agree. But, anyone who lifts and puts larger wheels and tires on ANY 4x4 should have already planned for gears. I see it everywhere though... " why is my lifted and oversized tire combo Tahoe/F150/Express/Jimmy/Durango a slug? "
 

Marky Dissod

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What I was getting at is ... sticking with GMT800s for now ...
When I learned of some GMT800 vehicles (including not suvs) that came with axle gearing under 3.73, I was momentarily shocked, until I remembered why GM undergeared every single vehicle with a V8 for the past 49 years.

Then on top of that, yes, most people who increase the weight of their wheel & tire package, fail to account for the decreased leverage of their new wheels & tires?

"Because it was already undergeared by the factory - then you undergeared it quite a bit more with those wheels and tires that also weigh a lot more."
 

Mudsport96

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Agreed. And I can concede that say a 2wd standard cab truck would be fine just for running to town with like a 3.42...in flat as a nickel Lincoln, Nebraska.
But, any 4x4 should have a minimum of 3.73s.
Fun fact: in the early to mid 90s Ford made an F150 that had a ZERO lb tow rating. So if you think a 3.42 tahoe is bad.... try driving a 300 inline 6 cylinder truck with a 2.73 gear.
 
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ValleyTahoe

ValleyTahoe

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So 3.73's are doing the 35's justice for now. I am going to get them done. I found 2 different L92 6.0L for $850 at the yard. I may snag one. What else is needed accessory wise, ecu etc?
 
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ValleyTahoe

ValleyTahoe

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Agreed. And I can concede that say a 2wd standard cab truck would be fine just for running to town with like a 3.42...in flat as a nickel Lincoln, Nebraska.
But, any 4x4 should have a minimum of 3.73s.
Fun fact: in the early to mid 90s Ford made an F150 that had a ZERO lb tow rating. So if you think a 3.42 tahoe is bad.... try driving a 300 inline 6 cylinder truck with a 2.73 gear.
Turns out I got luckier than I thought. Ran my RPO codes I got 4.10's. Truck is on the ground jamming. IMG_3405.jpeg
 

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