RAM357

My dad and I are in the process of gathering all the information and making decisions on doing LS swaps in our 2004 and 2005 LJs, and we're currently struggling over a decision on going with a 5.3 or 6.0...

We are not interested in taking the Jeeps to a drag strip or doing extreme climbing (at least not yet), but we do want the results of the swap to be Jeeps that are REALLY FUN to drive. It would be awesome to pull a decent sports car from a light to around 40 or 50mph!

My Jeep is a daily driver (very short commute), and my dad's is his toy. We have very moderate setups. Mine is a Rubicon with 33s and 4.56 gears, and my dad's has 32s and 4.11 gears... We are currently running autos and plan to go with the 4L60E in the swaps with our NP241OR and NP231 (for now at least)...

For you guys who have experience with both the 5.3 and the 6.0 in a Wrangler... here are our questions:

• Will the 5.3 put a really BIG smile on our faces when we drive it? Or should we go with a 6.0 if we want real excitement? (I'm leaning toward 6.0)...
• Does the 6.0 require 92 octane or better (we've heard yes and no)?
• For normal daily driving what is a realistic difference in gas mileage between the 5.3 and the 6.0?
• We're pretty confident we can go with the 6.0 for around $1K more than the 5.3 (either with less than 20K miles)... Is it worth it?

I know... with one breath I'm talking about pulling a sports car and the next breath I'm talking about gas mileage. Guess I want to have my cake and eat it too!

I'm really interested to hear your thoughts...

Thanks,
Rob

SSilver

5.3 should be more than enough...

http://www.youtube.com/watch?v=_3rxziQZMII

welldonecj7

iTrader: (13)

Both can make really good power, I am kind of in the same boat as you trying to decide, I might swap my crate 350 out for a newer ls style engine. It all depends on the goals of the jeep and what you think you will do down the road. If the money isn't a big deal I would go with the 6.0. They will make very good power, make some more torque and lots of potential if you want to build in the future. The 5.3 however can be made into a great engine also, for the money difference in the two you could easily make more power with the 5.3 then a stock 6.0 makes. The MPG will prob be slightly better with the 5.3 but I would not expect a huge difference on similiar builds (however may be wrong). I think either way you go you will be happy, they are awesome engines. The ly6 would be a good one to look into also with the l92 heads on it from the factory. As far as the gas goes lq4 will have lower compression than the lq9 6.0 so it will be a little less picky on the fuel, so if you are concerned with having to run premium this is something you should consider.

bczee

iTrader: (12)

I'd say a 5.3 will do.. why don't you go and drive a few trucks with these engines and see how you like them in the 1st place. I don't think your going to notice too much difference in normal daily and highway driving, unless you have a heavy right foot.

-You should be able to run regular fuel if both are stock.
-As far as cost, your about right.. 5.3 are very cheap... with a LQ4/9 for less than $500-$700 more as a pull out price.
-Going with a 6.0, yes more HP but more inportant is the Torque.

SSilver's CJ looks like it gets up and goes pertty good ! ...

drop in a mild cam and that shuold be more they you could use for most off roading trips.

Just my 2 cents..

garys 68

iTrader: (1)

The 5.3 should be fine, but...........
I've never met anyone who wished they had a smaller engine. And if you're ever going to tow anything, the 6.0 is an easy choice.
All motors will run fine on regular gas, they have knock sensors that will detune if you're running them hard.
As for fuel milage, I went from 12mpg with my sbc, to 26mpg with the 6.0. A 5.3 might have been good for another 1-2mpg, but with 4.56 gears in your jeep, you probably wont notice much difference.

71ANTICARB

iTrader: (23)

Here's what I would since your's is a dd and your dad's is a toy, I would put a 6.0 in your dad's and see how you like it. As far as mileage goes I have an 05 Silverado 2500HD (6.0) ex cab 4x4 w/ 32s on and average bout 12.5 mpg, my buddy has an 04 Silverado 1500 (5.3) reg cab with 36s and bout 7in of lift and get bout 14 mpg. We both run reg in our trucks and run em pretty good with out beatin the **** out of them. I think either one will offer enough power to do whatever you are plannin on throwing at it.

poconojoe

iTrader: (43)

Personally for your DD I'd go with the L33 5.3, it has more power then the regular 5.3's, plus its the aluminium block version and will weigh less. As far as your father jeep, I'd lean towards the 6.0, since it wouldn't mater as much, if it got less mileage and it will. Plus with your lower rear gears, you'll be reving the motor higher, since your one inch bigger tire size isn't going to cover the differance in gear ratios

RAM357

A lot of good thoughts... I appreciate the responses so far...

Just out of curiosity... Which 6.0 did you go with? Was that an LQ4?

garys 68

iTrader: (1)

I went from a "big cam" 350 4 speed muncie to an LQ9 with a Richmond 6 speed. My build thread is on here somewhere. The LQ9 already has the LS1 cam, high compression. Add headers and a mild tune and it overpowers my stock wheels/tires in most gears.

SSilver

I'll never say I want a smaller engine but I will say I want better axles and bigger tires to actually put the power to the ground. Put a new (used) set of BFG AT's on today because one of the other tires blew....lights up 31's at 1/3 throttle in 2nd gear

bagged67camaro

iTrader: (4)

Just 1 thing some years of the 6.0 the 4l80 trans are the only ones that will work thicker flange on the crank but the 5.3 there crank is the same as the ls1 so the t56 and 4l60e will fit just wanted to let ya know.

gofastwclass

iTrader: (2)

This statement is not quite correct. The "early" (1999 and some 2000) 6.0's have the thicker crank flange. The flange is .400" longer than a typical Gen III / IV engine and thus is EXACTLY the same depth as a GEN I / II engine. This means any transmission that works with a GEN I / II engine will work with those without an adapter. GM and others sell adapters and longer bolts to convert GEN III / IV engines to GEN I / II transmissions and the other way round. There is a picture of the GM adapter with part numbers in my Thunderbird build topic on the first page.

The easy way to spot these early 6.0 engines is cast iron heads or the crank flange sticks out past the seal like an early SBC. There were some reported to have been built with aluminum heads, but I haven't seen any.

Honestly the power difference between the 5.3 and 6.0 is so small it really isn't worthy of paying the extra money for the pricer 6.0. Add a Z06 or HOT cam and springs to the 5.3 and call it a day. There is a dude on Pro Touring with a stout NA 5.3 using mainly stock parts just to prove the point - and it wasn't crazy expensive.

Bo185

The LQ9 will need 92 gas to get most HP. The LQ4 will run fine on 87. But by a 5.3L add a cam and enjoy! If not enough a 6.0L will bolt right in its place!

RAM357

I appreciate the posts about the fitment issues... that's the sort of thing we're wanting to educate ourselves about as we prepare for this...

We've pretty well decided to pursue the LQ9. We're not very interested in high RPM performance. The thing that is beautiful about the LQ9 if you look at the factory dyno is the torque STARTS at 300 ft lbs at 1K and goes up to 380 ft lbs around 4200...

For our purposes those numbers look terrific...

RAM357

Well, we're goin with a LY6...

Got it for about the same price as the LQ9s we were finding...

Doing Dad's Jeep first. Then will swap one into mine...

Probably about a month until we start... will update on progress...

welldonecj7

iTrader: (13)

I have been looking at those ly6 also, however with the variable cam timing I dont know if I want that, so then would have to convert to ls2 style front cam cover. I also didnt know if those would be harder to get running in a swap vehicle than the older gen III style 6.0 and 5.3. The l92 heads from the factory are awesome and the engines go for decent price like you said so the seem like could be a good engine to go with, keep posting updates with your progress.

Anyone know how difficult these are to get set up as far as wiring etc.?

buddyholly

The LY6 is a great choice. I just installed one in my '76 GMC. The Gen IV computer is much more powerful than the Gen III's. Wiring is about the same all in all. The L92 heads are worth the effort. The VVT is nothing to be scared of and a must keep if you stay with the stock cam. All your low end torque and then full high end horsepower. I am tempted to add vvt to the L76 motor I am building for my Chevelle.

welldonecj7

iTrader: (13)

If i end up going with the ly6 I would prob just keep it stock for a while, thus running the veriable timing, however if I was to swap out I would prob just run a standard type cam and get rid of the variable timing.

Can you swap the ls3 intake and keep running the truck accessories?

jeeprats

I have a 2006 new LQ9 6.0 in my jeep wrangler because I thought is would be nice to have the option to tow a small 16 ft trailer. I put a 4L60E trans with a stock transfer case. I also would also highly recommend that you manage your build and not do as I did which was to let a well known company do the install. When finished, I will have spent additional $5,000 cleaning up their bad install. The jeep is so fun to drive with this engine and I run regular gas and get 18mpg on the road and 14 in town. Problem is I love the sound of the engine and love to hit the gas pedal. The build will be expensive even if doing it yourself. A friend bought a camero and used all the parts. That is the way to go cheap. My way using a company that had poor organization and poor mechanics could cost you $19,000 to complete.