bfschor

I would agree with you about the 5.3 in the Yukon...its a little under powered for that. I had one in a 2001 1/2 short bed regular cab with 3:73 gears and it did quite well. I only had it for a little less than a year because I couldn't get the dealer to do anything about the loud ticking at start-up. The dealer said they all do it and it's "normal". My dad had bought a 2001 Duramax and he traded his off the same time I traded my 5.3. The dealer would give him a gallon of oil and a gallon of anti-freeze saying "we think we fixed the leak this time". Those were our last GM vehicles. I would hope by now the 5.3 doesn't sound like a rattle trap when you start it. I haven't heard any complaints recently. I had a Hemi in my last truck and my dad has one in his now - we both love them.

I like the idea of the 5.3 in terms of weight and for a 2-door JK, it should have plenty of power. Though I'm not one of these guys that say "why do you need that much power". I'm always one to take as much as I can get....it's not a thing of need, but of want. At the same time, I'm not about to throw $30k on an engine swap in a Jeep. I can stomach around $20k, but it's still a little hard - hence this thread.

I definitely like a clean, factory look. I would love to be able to open the hood and not have wiring and or tubes going everywhere. I am strongly considering the Hemi as I've seen pics of them in JK's...they look factory clean. I haven't seen too many LS JK pics, but the ones I have seen, I thought they looked pretty clean as well. I hear what make the LS shine is the tranny, which is something I'll need as well. Apparently, my 6-speed doesn't play well with anything but the V6. Which is fine....I kinda want an automatic anyway....I hate worrying about muddy water.

Biginboca

One other consideration is the added weight of the Hemi over the LS. I remember reading the LS conversion only adds maybe 50lbs while the Hemi adds hundreds, needing suspension adjustments to handle the weight.

When/If I do a V8 I'll be doing the LS it seems like a better platform for the jeep. Runs cool, light weight, plenty of power, and better transmission.

bfschor

Yup, I've read this same thing. I take that it's comparing the 5.3. I'm not sure how the weight of the larger liter aluminum block LS engines compare with the Hemi. I've always tried to keep my jk on the lite side.

I've also read that if you do the Hemi, you've gotta alter your firewall. Not sure if that's true or not, but I'd prefer as few alterations as possible. (Though an engine swap is a huge alteration, but you guys know what I mean!)

un lupis

Well if you lived closer to me , I would hand you the key . but I'm not driving to Texas any time soon .
My Girl Friend has a JKUR and she is headed to Vegas as soon as she can collect all the pennies , nickels and dimes she needs to get hers done .
I own a JKR(2 door) hers is a 4 door . She wants the same engine and trans as I have in mine . I have the LS3-6.2-6L80E in mine .
She is continually asking to drive mine (begging more like it) . Hers is a '14' , mine '07' , her 3.6 is OK compared to the 3.8 that was in mine , but not anything I would call powerful .
The 6L60E transmission is the real key to these swaps in my humble opinion , I did indeed drive the 6.1 Hemi , 5.7 Hemi and both the 5.3 LS and the 6.0 LS . The only one of the others that gave me what I expected from the expense invested was the 6.0 LS , the 6.2 and the 6.0 LS are pretty darn close to each other , as far as the seat of the pants feel is concerned . The 6.0 is a iron block and is heavier and that I didn't want .
Where the Hemi failed to pass my approval was in regard to the transmission , it still had the propensity to hunt gears , much like the transmission in my JKR did , I found that annoying .
The 6L80E is never in the wrong gear and it does not hunt gears at all .
I call the Chrysler transmissions the Joe Biden of transmissions , they are in my opinion just not well designed or developed to the point that the General Motors transmissions are . GM spent nearly a million dollars on development on that transmission (or some such stupid amount) I read a report early on in my research and don't remember how to find it , but it should still be available to find it .
If you get a chance to drive a few of these different swaps it can really help you decide . Robbie has a 6.2 and a 5.3 on site if you wander to Vegas any time soon , available to drive .
I believe there are purists who will say that nothing other than a Chrysler should go in a Jeep , and early on I would have thought that, that would be the easier of the swaps and would look cleaner . But the LS looks like it belongs in between the frame rails . It for the most part sits lower in the engine bay than the Hemi does and is just marginally lighter too .

The more questions that you get answered the more questions you will have , at least that's how it went for me .
Sorry for the long post , but I got carried away .

Da20captain

Alterations to the firewall are somewhat dependent on which kits/exhaust manifolds you use. Dakota, I believe, may use the truck manifolds. If you use the Grand Cherokee manifolds no bashing of firewall necessary.

Very true about questions and answers. The more answered the more asked.

But one thing is for shit sho, when you get a V8 whether it be LS or the Hemi, you will be stoked.

bfschor

Ugg...I wish I did live closer! I have a JKR as well. What's your gear ratio and what size tires are you running? And what didn't you like about the 5.3?

Flights to Vegas from DFW are usually pretty cheap. If I can't find any to test drive around here (I don't see many 2-doors, much less with V8's), then I'll see about flying out to talk to Robbie.

scubatech

The Hemi weighs about 150 lbs more than a 3.6Liter & 100 or so over a 3.8L according to All Par. The steering column on mine was moved over a 1/2" if I remember right. There is no suspension issues with the weight of the engine. I'm surpised that Mopar hasn't yet meade the Hemi block out of aluminum.

un lupis

bfschor , I'm on 37''s and 5:13 gears , need to change to 4:10 or 4:88 gears . Not really sure that I will , I kinda' like the hotrod feel of it now .
As far as what I didn't like about the 5.3 , I liked it , I just liked the 6.2 a whole lot more .
When I drove the 6.2 it really opened my eyes , a oh wow moment .
And every time I get in it now , I get the same feeling .
I didn't want to say to myself later on that I should have bucked up and got the 6.2 later on , and feel remorse .

I would not say to anyone "you'll be fine with a 5.3" without at least having the chance to make that determination for themselves .

Whatever you decide on for yourself , a V8 in the JK is how the JK should come from the factory , at a minimum it should be an option at least .

Chrysler is missing out on lot of money by not having the clarity of sight to see that the aftermarket has stepped into a profitable arena , and that money is setting sail without them .

ntropy

bfschor, great post and lots of good input you're getting. I'm in a similar boat: I have a 2010 with 135k miles. It's a heavy sucker with all the armor and stuff I've put on it. I need another year to save up for a swap, but I fully plan to. Hope my JK makes it until then; it's my daily driver. BTW, I'm in Arlington. Love to compare notes some day if either of us make this happen.

Big question I have is emissions testing. As you know, we have tough testing due to air quality here in DFW. How hard is it to pass inspection with either Hemi or LS? Sounds like there ends up being two OBD ports with an LS; how would the test happen?

I'm leaning towards a Mo-tech LS for all the reasons folks have mentioned, but I don't want to put myself in a situation where I can't keep the Jeep registered due to inability to meet inspection requirements.

Any thoughts?

thanks

RockTurtle

I know this is probably irrelevant for the OP, but with the Hemi, there is the possibility to keep a manual transmission without any check engine lights or anything.. Of course, the stock NSG would last about 3 days... so you would have to swap to a Getrag 238 trans. But the option is there.

IF I was looking at a swap, that would be the ticket for me... 5.7 Hemi with the Getrag. Something about a vehicle with a V8 and a manual transmission...