LB7 build/ LLY swap

Lb7Sam

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Recently bought a wrecked lb7 for dirt cheap from a friend. Pulled the motor, stripped it to the block and sent it to the machine shop to be hot tanked, honed and new cam bearings. In the meantime I’ve got the cab and bed off and basically stripped it to the frame. It’s going to be my winter project to re-do it. With that being said I’ve been tossing around the idea of doing an lly top end swap. I was planning on building for some power and replacing the heads regardless and get cupless heads if I go the lb7 route. Just looking for some opinions on if it’s worth the extra money to go after the LLY top end swap or stick to the LB7 platform. Any and all help is appreciated.
 

TheBac

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Deleted your duplicate thread and combined the thread names for this one.

What year truck are you starting with? 03-04 will be easier to do the LLY swap. How do you plan to source the LLY parts?
 

Lb7Sam

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Deleted your duplicate thread and combined the thread names for this one.

What year truck are you starting with? 03-04 will be easier to do the LLY swap. How do you plan to source the LLY parts?

Thanks, starting with an 04 lb7. Was either gonna just get new or source them from Hicksville auto recyclers.


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Bdsankey

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In my personal opinion the LLY swap offers no gain anymore now that we have SAC injectors. The only gain, IMO, that can still be argued is the VGT turbocharger.

A quality SAC injector for an LB7 lasts just as long as an LLY+ truck as it's the exact same nozzle type.

I did have a few questions tho:
1) What are your goals for the truck power wise?
2) How do you use the truck
3) What elevation do you live at? Based on your profile I'm guessing around 1000-1500ft being in NE Ohio.
4) What else is done to the truck?
5) What is your budget?
 

Lb7Sam

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Aug 30, 2024
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In my personal opinion the LLY swap offers no gain anymore now that we have SAC injectors. The only gain, IMO, that can still be argued is the VGT turbocharger.

A quality SAC injector for an LB7 lasts just as long as an LLY+ truck as it's the exact same nozzle type.

I did have a few questions tho:
1) What are your goals for the truck power wise?
2) How do you use the truck
3) What elevation do you live at? Based on your profile I'm guessing around 1000-1500ft being in NE Ohio.
4) What else is done to the truck?
5) What is your budget?

Yeah the only gains that I figured were still arguable would be the turbo and access to injectors. I’d like to be around 700hp maybe a little less but wanna make it there reliably. Trucks mostly daily driver occasionally hooking up to a trailer to pull a mini excavator. Truck was bone stock but is completely gutted at the moment. As far as the budget I’m really not sure. Haven’t set a number in stone but hoping to keep it around 10k maybe a touch more for the motor.
 

Bdsankey

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Yeah the only gains that I figured were still arguable would be the turbo and access to injectors. I’d like to be around 700hp maybe a little less but wanna make it there reliably. Trucks mostly daily driver occasionally hooking up to a trailer to pull a mini excavator. Truck was bone stock but is completely gutted at the moment. As far as the budget I’m really not sure. Haven’t set a number in stone but hoping to keep it around 10k maybe a touch more for the motor.
For 700hp and towing I would do the below myself.

Engine: Callies rods, either delipped LB7 or Mahle Motorsport pistons, OEM crank, small cam (no reliefs), main studs, ARP 625 (I urge most people to go right to 625s when building a motor, we all know the bug never stops)

Air: stock/S480 compounds, could go to a stage 1 drop in/S480.

Fuel: 10mm or 12mm CP3, SAC100% injectors, 165gph lift pump (I prefer Airdog)

Trans: Built with OEM hard parts, Goerend G converter works well with OEM LB7 chargers in the valley.
 

Lb7Sam

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Pardon my ignorance but what do you mean by Oem hard parts as far as the trans? And what about an s379 or 366? First time diving into all of this and just soaking up all the knowledge I can get.


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Bdsankey

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Pardon my ignorance but what do you mean by Oem hard parts as far as the trans?
Stock shafts, hubs, planets etc. IE no billet internal upgrades are needed in my opinion for a 700whp unit.


And what about an s379 or 366? First time diving into all of this and just soaking up all the knowledge I can get.


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If you're towing heavy I personally would avoid a S366 or larger. There is not a faster spooling turbo than the factory LB7 turbo, especially if someone takes the time to port/polish it (retaining OEM wheels).

With compounds, you get that drivability plus EGT reduction and HP headroom due to the extra airflow from the atmospheric turbo.

A 65-66mm drop-in turbo will get you to your goal as well (or damn damn close in that 650-700whp range) and drive very well. I went compounds on my personal LB7 for that reason. My HP goals are a touch higher which is why I went S300/S400. I typically don't use over a 64mm drop-in with a slightly upgraded turbine on things that tow heavy as I do not like how unresponsive they are.


The S364.5/68 spools about the same as a smaller drop-in turbocharger but does flow a fair bit more, it also costs significantly less. This matters because by the time I purchased the compound kit AND an upgraded drop-in turbo it is comparable in cost to the S300/S400 setup once you factor in the cost of turbos. If someone is doing it all at once then this is absolutely a viable option.
 

Lb7Sam

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Thanks for the info man, you think stock crank will be just fine or should I have a key cut into it? Or just replace it while everything’s apart for longevity’s sake? And probably a dumb question but with stock/s480, 100% overs, and 10mm how smoky will it be as a daily? Or is that all in how it’ll be tuned?


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Bdsankey

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Thanks for the info man, you think stock crank will be just fine or should I have a key cut into it? Or just replace it while everything’s apart for longevity’s sake?
Using the OEM crank does not bother me but yes, I would key it. My apologies for leaving that out, I am so used to that being assumed in most of the chats I am in so that is my bad.

If there is budget for it, a callies compstar/durastar crankshaft is never a bad ideal. They are stronger than stock and are new/virgin, not with millions and millions of firing cycles on them.

When the time comes reach out to me, we carry everything and ship most everything free except freight items.



And probably a dumb question but with stock/s480, 100% overs, and 10mm how smoky will it be as a daily? Or is that all in how it’ll be tuned?


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Not smoky at all WITH a proper converter and good tuning. I have many customers with that setup as well as many customers with significantly larger street setups which all run extremely clean.

Good tuning, good injectors, properly spec'd turbos, and a properly spec'd converter ALL lead to a better driving experience.