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LS swap 5.3 vs 6.0

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swampjeep

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sorry if this question has been here before, I've been in and out over the past years, but can't seem to find a thread like this.

I'm getting ready to do a build this winter and considering an LS motor, so for those of you who have done it, what would you say to do, a 5.3 or 6.0?

I'm sure it will much depend on the use, but I'd like to hear what you have to say about what you like/don't like, and if you are happy, or wish you had done something different.

I'd like to build this as a general all around vehicle. Not that I will DD it all year, but would like it to be something I could if I wanted or needed to, plus drive it up to the trails for some family 2 tracking, or run out to the dunes. I would bet a 5.3 would do me well, but curious if I'd be better off with the 6.0 considering the sand dune usage, or would I be giving up too much fuel economy and kick myself on ever camping trip. I plan to run 33" tires, possibly keeping my 700R4 and NP241 I have now.

Oh and the biggest question, is it really worth it over a TBI350 for this type of usage, my guess is yes, but again, looking to those who have it to see what they say.
 
the 5.3L is a damn fine motor.

but most buggy's that are ls powered are running the 6.0L for the sheer power that it can produce. Not saying the 5.3 can't make power, but the 6.0 is tried and true.
 
FWIW, I got 19.7 mpg on the highway with my Silverado which has a 5.3... I say if you are doing any long highway driving, get the 5.3. I think it has more than enough power to move a Blazer. Anything bigger than that and I would consider going a 6.0. If you are planning on upgrading the rig, keep that in mind too. You may not stay at 33's for the time you have the truck, and eventually want more power.
 
I do agree that at some point I may make it more "dune only" or bigger tires or...
so how much will I suffer in fuel economy with the 6.0?
or what could I expect with a 6.0 with using a computer in "economy" mode?

I'm really hoping some people with each in their K-5's can chime in with some reports to help me decide.
 
When I was looking to do the swap it was a pretty easy decision based on money alone. The 5.3's are cheaper, the 6.0's make more power. I found an affordable 6.0, but had one not have came along for a price I wanted to pay I would have had a 5.3 and spent a little bit more money for a cam and had it run about like a stock 6.0. If you want to over pay from one of those turnkey places that pulls motors out of the junkyard and marks them up 400% buy a 6.0 since you're already into it that much.

My GMC is in the single digits for mileage with 38" boggers but it does pretty good in the dunes and other areas that require some horsepower. I dont imagine you would notice a difference in fuel consumption with a 5.3 when the tires get big and the terrain requires the throttle. What you would notice would be the difference in power.
 
5.3 has a better bottom end. Theyre all forged bottom ends from the factory hence why guys looking to do turbos or a blower on the somewhat budget end opt for the 5.3 over 6.0s.

That being said my friend jeep buggy has a 6.0 with a 93 octane tune and its a ****ing animal.
 
I've been out twice with my k5 since the 5.3 swap and it's had more than enough power running on 38in boggers. Haven't driven enough on the streets with it to check mpg but it does very well on the street too. My DD is a 01 with a 5.3 and 35s get 12.5mpg
 
I've been pretty much sold on doing a 6.0 swap vs a 5.3 just thinking I'd want the power, but I'm starting to reconsider. I've been waiting for the right 6.0 deal to come along for awhile now and it just hasn't happened. meanwhile, 5.3s are a dime a dozen.
 
Stomis said:
5.3 has a better bottom end. Theyre all forged bottom ends from the factory hence why guys looking to do turbos or a blower on the somewhat budget end opt for the 5.3 over 6.0s.

That being said my friend jeep buggy has a 6.0 with a 93 octane tune and its a ****ing animal.
Click to expand...

5.3 and 6.0 share the same bottom end,rods,crank etc,the only difference is the size of the bore.

That being said the power difference is not that huge between the two but the 5.3 generally is way cheaper. Plus with that price difference you can stuff a better cam and valve springs in it and and make the same power as a 6.0 and still probably be cheaper.
 
I chose the 6.0 cause I want to build my truck up for towing and like a 2500. I happened to come across one that I knew was good, and that had a cam stuffed into it.

the 5.3 just seems to lack the torque and pull a 6.0 has.
 
The 5.3 does not have the torque, that is for sure, but the money saved over a 6.0 it wont have a problem making more torque with a cam, springs and a lil bit of headwork. Plus, the dime a dozen thing kicks into play here. That being said my brother has a stock 6.0 out of an escalade and it turns his 38s about as good as my warmed over 7.4 turns my 39.5s, in the same pig suburban. Food for thought....
 
Babaganoosh said:
I chose the 6.0 cause I want to build my truck up for towing and like a 2500. I happened to come across one that I knew was good, and that had a cam stuffed into it.

the 5.3 just seems to lack the torque and pull a 6.0 has.
Click to expand...

is this in a K5? how is it built up, and how bad is the fuel economy?

Fuel economy isn't my ultimate goal, but I don't want in the single digits on 33's.

I've seen complete trucks with higher miles but still running great for $1000-1500 with 5.3's and 6.0's, I'll probably pick up on a truck like this when I'm to the engine point of the build.

thanks for the info guys, and please keep it coming, the more real world feed back I can get should help with my decision.

I'm really curious what I could do to a 6.0 to obtain the best fuel economy on trips, but still have the displacement to bump it up without much work if I decide to turn into a beast later, or have more toque for towing etc.
 
I guess Ill jump in here too with a few questions since this swap is on the horizon for me as well. Mine will be going into an 87 Burb with a 2 inch lift and 33's. This is my hunting rig and sees a ton of highway driving...if I pull anything it is a small utility trailer and maybe a 16 ft Lund now and again but not huge distances. My question is because of the size of the Burb would I be better off jumping up to the 6.0 to start? I like the fuel economy and options to help increase power in the 5.3, but I would hate to go through the swap and wish I had more to get the Burb rolling. I plan on swapping in a 4l60/4l80 with the motor as well if that makes a difference. The Burb has 14bff rear and 10 bolt front with 4.10s. I will never go bigger than 33s and this rig is my dd through the winter up here. Any input is welcome, not sold on Any one particular swap yet, but have a yard nearby that has a ton of 5.3s and 6.0s for around $750 with around 100k miles. . .
 
If it helps you decide any, I have 2 friends with tahoes, one it the standard, one is the XL (basically a suburban) with 5.3's and they keep telling my the 5.3 is all I'll need and they are happy as can be with the power and fuel economy, even towing a 4000lb jeep on a trailer behind it.

I'm not 100% sold because my K5 might end up more of a dune toy and I dont' want to be sorry if it does. If it wasn't for that, I'd probably just do the 5.3 and not even post this question.

is that $750 for everything? all accessories, wire harness, DBW throttle, computer...

I've been told to make sure you get everything together if at all possible, or expect problems getting everything to work together.
 
Regarding fuel mileage between the 5.3 and 6.0 that is a really hard answer to question. Lots of people will chime in and say the 5.3 gets a lot better mileage but they also are not taking into consideration the other variables, which is the truck they are in. There are no 5.3 powered 2500 trucks out there and very few 6.0's in 1500 trucks, so almost every gas mileage comparision is looking at a 2500/2500HD truck vs. a 1500. Of course the mpg is going to be worse on the 2500HD with the heavier drivetrain with higher parasitic lossses (4L80 vs. 4L60, 14FF vs. 10-bolt, usually lower gearing, etc...) and heavier overall weight.

But in the end I would say whatever engine you can find the best deal on.
 
Thanks for the insight swamp. I'm thinking the 5.3 will be fine for the hunting rig and still have plenty of power for the amount of towing I do. I've talked with the salvage yard here and the engines come run ready with all accessories and wiring. They are anywhere from $550-$750 depending on mileage, so like 6.2 blazer, I'll probably end up getting the 5.3 since they are typically cheaper.
 
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