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Needing Advice on an Engine swap!!!

MontanaH3Guy

Member
Messages
12
Location
Montana, USA
Hey everyone, I've been an H3 owner for several years now my 3.5 finally died. I've made the decision to engine swap to a V8 and have a bunch of questions. Any advice or help would be greatly apricated. My first big question is about what motor to buy. There were so many variants of the 5.3L LS I'm trying to but this together with as much OEM parts as possible. I just got off the phone with my local wrecking yard and he tells me that the LH8 and LH9 motors are getting hard to come by and one would pay a pretty penny for them. He suggested looking into the LC9 motor. I'm wondering if anyone on here knows if the LC9 would be a compatible fit to the OEM alpha electronics or if they wont match up at all.


hummer.jpg
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
Welcome! I can't help you with your questions but someone will pop by that can. Glad you're keeping your H3!
 

atvspeed4

Well-Known Member
Messages
1,173
Location
massachusetts
Get the biggest displacement "LS" you can find. It makes no difference in the parts you use for the swap. I have a stock 5.3 alpha, a cammed 6.0L alpha and a 2006 6.0L vvt/ 6L90 swapped H3. I cant think of a time that I wished I had the 5.3L in all trucks. If you get a motor with cylinder deactivation "D.O.D or AFM" you will need to do a delete but its not a big deal when motor is on a stand. A 2010+ silverado 2500 is a great source for 6.0L that does not have cylinder deactivation and has great heads and lower end.
 

06 H3

a.k.a. "The Jackal"
Messages
9,350
Location
Meridian, ID
Agreed. I went from the 3.5 to the 5.3 to the 6.2 and the 5.3 to 6.2 had almost no wiring changes, just pcm tuning. Go as big as possible
 

MontanaH3Guy

Member
Messages
12
Location
Montana, USA
Thank you guys for the feed back. This has been by far one the most frustrating thing's I've looked into. I feel like the more research I do the more complicated it becomes. I'm looking at a 3/4 suburban with a 6.0 in it as donor for this. Any recommendations or major issues I should watch out for? I've heard stories of the gas peddle gages and keys not working with this swap. I've owned a lot of cars in my time and the H3 has been one of my absolute favorites, Its become part of the family.
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
I haven't done the swap, but wouldn't it be ideal to look for an aluminum block vs. an iron block? I think all 6.2s and 5.3s are aluminum, while 6.0 can be either. Just use common sense. FOR example, the 6.2 in my Silverado is designed for a truck, with a bit lower HP and higher torque than the 6.2 I had in my Camaro.

06 H3 pointed out that the jump from 5.3 to 6.2 is as much as the jump from I5 to 5.3,ao just go for the bigger displacement engine for the biggest grins


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amrg

Well-Known Member
Messages
2,317
Location
Qatar
Get a truck 6.2 aluminum block with truck intake. The alum block reduces the weight on the front, the truck intake gices you the flexibility of keeping the clutch fan with the throttle body sitting 4" higher up (recommended) unless you're willing to fiddle around making an efan setup.

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atvspeed4

Well-Known Member
Messages
1,173
Location
massachusetts
Two of our trucks have the iron block not a big deal with weight (its around 110lbs difference if I remember correctly). I would highly suggest making sure that you get a 56x gen IV motor instead of 24x gen III. No changing of the gas pedal or ignition switch. Definitely get a truck intake/ accessories as stated above. Otherwise its just ordering harness, current performance motormount adapters and all the OEM alpha specific parts to make it happen.
 

jimmy p

Well-Known Member
Messages
186
Location
detroit
There are a couple questions you have to ask yourself first.

Do you want your stock gauges, traction control, stabilitrak etc to work?

Do you have access to someone who can custom tune on a dyno chassis?


In my opinion these are the primary drivers of what engine options you have.





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atvspeed4

Well-Known Member
Messages
1,173
Location
massachusetts
There are a couple questions you have to ask yourself first.

Do you want your stock gauges, traction control, stabilitrak etc to work?

Do you have access to someone who can custom tune on a dyno chassis?


In my opinion these are the primary drivers of what engine options you have.



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Really only should be swapping in a GenIV motor at this point in our community knowledge of swaps. Cheapest, most power for the $ and its a proven swap where all gauges, vehicle functions act like OEM. No need for a dyno tune. Our tuner jumped in with his laptop for about a 30 minute drive and made all the adjustments we needed. If you are keeping a 4l60e the tuner will usually start with an alpha base tune and go from there.
 

06 H3

a.k.a. "The Jackal"
Messages
9,350
Location
Meridian, ID
All my gauges work. My 06 H3 that came with a 3.5L has no idea a 6.2L and non stock axles are under it. You can integrate everything without too much hassle. I even had it smog legal in the state of CA which is one of the harder states to please with emissions. It can definitely be done.

Go Gen 4 LS and I had a guy do a tune as I drove. If you must dyno it and it isn’t an AWD dyno just put it in 4Hi lock and then pull the front driveshaft
 

MontanaH3Guy

Member
Messages
12
Location
Montana, USA
Is there an easy way to tell what gen the motor is. VIN or number stamp on the motor. I haven't yet bought the motor and was looking at a couple 5.3 out of a wrecking yard here until my friend said they may have an 03 suburban that has a good 6.0 motor and good trans (it was in a roll over so the body is toast).
 

amrg

Well-Known Member
Messages
2,317
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Just find a 6.2 and you will be good to go

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crwalkerasla

Well-Known Member
Messages
313
Location
Corinth, MS
I'm considering the same engine swap, but am concerned about the trany holding up. I am on my 3rd transmission and if it's not doing well with the I5, I am really concerned about strapping a 6.2L to it.
 

amrg

Well-Known Member
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2,317
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It wont hold, be prepared to throw lots of money at it and pray [emoji16]

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rascole

Well-Known Member
Messages
2,580
Location
Bellflower, CA
from my recent research, and purchase, a 6.0 iron block can be had for as little as $800 running. Do you really want to put a used motor in you H3 after all that work to swap it in? It is worth the tear down/rebuild price to ensure a 200k mile motor. A used 6.2 can be had for as little as $3500, if your lucky and a LH8/9 are $2500+ if you can find one.
A $2500 rebuild will get you a stroked 6.0 and make more power than a stock 6.2 that you will still have to spend $1000 to freshen up. If your pockets can afford it, stroke a 7.0.
 

amrg

Well-Known Member
Messages
2,317
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@rascole you forgot to tell the OP that once he breaks the 450 hp level the entire suspension and front drive train will need looking at, not just the trans.
A stroked 7.0 though!

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