LB7 - Ultra Reliable 600 RWHP Build

sneaky98gt

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Nov 5, 2013
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Thinking about long-term plans for my truck (2003 CCSB 4x4 LB7). Let's say the goal is 600 rwhp (or enough to run 7.99 in full street trim in a 7000 pound truck) and to be as reliable as possible in a ~450-500 rwhp daily driver tune.

I'm defining "as reliable as possible" as the closest to brand-new GM longevity as could feasibly be done (recognizing that doubling the power output will still have some inherent detriment). In other words, you could go turn the key in 0-degree temperatures, tow a 10k pound trailer cross-country through 100+ degree temperatures, with it behaving exactly like it did when brand new with 0 miles on it in 2003. Doing all that while not having to worry about throwing a rod through the block, cracking a piston, lifting a head, etc. if you beat on it some. Oh, and doing it for 200k+ miles without decreased service intervals (or at least minimized). I'm basically looking for maximized peace-of-mind.

From a complete powertrain perspective (motor, fuel, & air), if money wasn't an issue, how would you do this build?

I've got a few ideas, but wanted to hear from those of you with more experience. 600 rwhp recipes are pretty common these days, but I wonder how many of them will last 100k+ miles without touching them.

Some things I'm considering:
- Oil-only cooled turbo vs. water & oil cooled
- GM vs aftermarket materials stability (crank, rods, & pistons)
- Stock vs. modded CP3s
- Alternate fire vs. standard cam
- The "little" things like bearings, rings, hardware
- Other "replacement" items to possibly be done (wiring harness, water pump, oil pump, etc.)

Thanks!
 
Last edited:

TheBac

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Well, if you want ultra-dont-worry-about-it-ever reliable, buy those lesser-expensive-but-still-really-good rods from SoCal (I forget who makes them),
upgrade the pushrods/springs/fasteners in the valvetrain,
should probably run 100% injectors and a 10mm CP3 minimum,
S400 turbo (T4 foot, smaller A/R so it spools faster.....but others here know more than I do about them)
use a good quality balancer and flexplate and have the rotating assy balanced by the machine shop.

Thats whats I would do.
 

WolfLMM

Making Chips
Nov 21, 2006
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SoCal street rods
SoCal billet crank
Springs, retainers, pushrods
Fingers pistons
100% injectors
12mm cp3
Headstuds
Keep the injector pulse at or below oem settings.

jmo
 

MAXX IT OUT

<<<IT WORKS
Mar 1, 2013
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Des Moines, Iowa
This idea of making a reliable 600HP always snow balls into a engine that is capable of making 1000+ HP. So if money isn't a issue, call Socal and tell Guy to throw the everything at it, but I would suggest doing a LLY conversions
Socal or wagler street rods
Mahle race cast piston
keyed stock or durastar crank if you need a new crank
Keyed stock Cam
2020 oil cooler
head studs and main studs
valve springs and pushrods
45-100% injectors with a 10mm cp3
Danville 68mm VGT
LBZ water pump
LML oil pump
 

OleBlackyLBZ

Active member
May 22, 2020
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Socal/Wagler Street Rods, Mahle Race Cast Pistons, ARP Head & Main Studs, New Stock Crank Keyed, New Stock Cam Keyed, Beehive Valve Springs & Some Pushrods, Wagler Pinned Oil Pump. Then a 10mm CP3, and a Danville 65mm Turbo if your really not going over 600.
 

sneaky98gt

Member
Nov 5, 2013
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I really don't have any intentions of >600 rwhp / faster than 7.70-7.90. 😇 But, I DO value a "can't-break-it" peace of mind.

I learned my lesson with my last ride: had a mod-motor Mustang (hence "sneaky98gt") that I owned for over 10 years. Slowly took it from a mid-15 second stock turd to a modified-everything mid-10 second street car (probably could have touched 9s with a converter change and a little suspension work). Over all those years, it was BY FAR the most fun when it ran high 11s / low 12s (mid-high 7s in the 1/8). When I started chasing more power beyond that, the fun factor went way down hill. Driveability suffered (NVH issues, general enjoyment, etc.), reliability suffered (seemingly ALWAYS had something to worry about going wrong), and having no traction below go-directly-to-jail speeds actually got old pretty quick. It was also way beyond something I'd ever consider letting someone else drive.

So my goals for this truck are to recreate what I enjoyed most in that car: relatively fast, but not stupidly so (a. la. high 7s / low 12s), but be able to go to it any time of day or year, fire it up and beat on it, with minimized worries of things going wrong. I also want it safe / hassle-free enough that I could, for example, loan it to a friend to tow 10k pounds cross-country and not have to worry about them being as much of a car-nut as I am to not grenade it (I'm aware tuning has a lot to do with this).

Rods seem to be a fairly easy discussion. Socal street rods and done.

For the pistons, it seems that Fingers pistons would be the bee's knees for what I want to do. However, I'm concerned about the "dirtyness" and/or haze that I've read about multiple times. Skip down to injectors below for further discussion. I'm also curious if the aftermarket cast pistons are made from a superior metal than stock pistons (serious question). The stock pistons obviously hold up to some serious miles, and relatively high power levels when treated right.

For the crank, ok, I know I said money was no issue, but $5k for a crank might be a bit much. LoL. Has there ever been consensus on what causes the cranks to break and/or things that can be done to help? For example, is it a reasonable path to: buy a new LB7 crank, magnaflux / inspect it, minimize weight of the pistons & rods, and balance the pistons and rods as closely as possible? And of course, balance the assembly as closely as possible?

Injectors. Are 100% over really needed for 600 rwhp? I was thinking I'd heard of guys making 700+ on 45% overs, so I was considering 45% or maybe at most 65% SAC injectors.. Keeping pulse width as low as possible makes perfect sense, but I'm worried about cleaning up big injectors. Recently had an injector go out, and the idle haze about drove me crazy. For something that would get driven a lot, I'd really like it as clean as possible (a.k.a. no haze at operating temps). Can you realistically clean up oval pistons (at say 16.5-17:1) and 100% SAC injectors to that level? A "slight haze" at cruising speeds that I've read about more than once is definitely not acceptable.

CP3. Are stroker pumps any less reliable than a stock one? I was leaning more towards something like a Sportsman as it's "less" modified than than a stroker, and therefore "more reliable", but I don't really have any evidence to support that.

Turbo. A smaller sized S400 I think would definitely get the power and driveability goals I'm looking for. But for just 600 rwhp, any reason not to go with a modified IHI and keep the water cooling? I've searched around before, and never seem to find people putting 100k+ on oil-only cooled turbos.

Springs, pushrods, and retainers are a given. As are head and main studs (I think, anyways).

Clevite H-series bearings (or equivalent from King).

Good damper and maybe a flexplate (haven't seen strong feelings either way on that one yet).

LBZ water pump is one that I intend on doing sometime anyway.

What's the scoop on the LML oil pump and newer oil cooler?

I intend to put together a semi-comprehensive price list at some point, which may be enough to scare me off the idea and just stick to a stock air/fuel, built-trans and leave it be. Then again, whatever that price is, it'll be less than a new truck, and I really like my truck anyway (a.k.a. don't plan to get rid of it / upgrade).
 

TheBac

Why do I keep doing this?
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Apr 19, 2008
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Shoot....You're describing my truck from back in the day, and that was on the old 12.40 tune, 30% injectors, lift pump, stock turbo and heads, cut LB7 pistons and LBZ rods and a set of caltracs with front QA1 shocks. Would do 12.40s all day long in daily driver trim and drive it all day if needed. Still runs fine to this day, but on close-to-stock tuning and stock suspension.
 

bimmer95

Member
Mar 16, 2019
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If your worried about haze with fingers pistons then go with mahle performance cast.Ive did more tune revisions since I put mine in and even got new tunes from a very reputable tuner and I'm still not quite satisfied.They are super strong pistons but for 600hp? Performance cast and run with it.Just my 2 cents

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MAXX IT OUT

<<<IT WORKS
Mar 1, 2013
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Des Moines, Iowa
What's the scoop on the LML oil pump and newer oil cooler?
The oil pump is supposed to flow more/more pressure, and the I believe you can use the LML piston squirters that also flow more to help with piston cooling. The newer oil coolers are from the L5P trucks are 15 or 20 row oil cooler vs the 10 row cooler on the 01-15 duramax's.
 

ikeG

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A new 17-19 oil cooler is cheaper than a new 01-10 oil cooler anyhow. Also a direct replacement with a few longer bolts. I put one on every engine I do.

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Bdsankey

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My LB7 build isn't far off from this concept, except it's power goal is higher.


I personally would do the following for your goals:
-10mm CP3
-SAC65% or SAC100% injectors
-64mm IHI or S475/stock kit (depends how often and how heavy you tow)
-SoCal street rods
-Mahle Motorsport cast pistons without reliefs
-SoCal 3388 cam
-SoCal or Manton valvetrain (springs/pushrods)
-Fluidampr
-BD Flexplate
-Wagler pinned/shimmed LBZ oil pump or machine an LML oil pump to fit then pin/shim it
-Mahle/Clevite "H" bearings
-2020 L5P engine oil cooler
-ARP everywhere (Merchant/ARP rocker shaft bolts also)
-Built trans with Goerend R
-Lift pump of your choice
-Danville/DHD water pump
-LML driver side manifold and 2" OEM manifold replacement up-pipes
-Quality DSP5 file
 

sneaky98gt

Member
Nov 5, 2013
109
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Shoot....You're describing my truck from back in the day, and that was on the old 12.40 tune, 30% injectors, lift pump, stock turbo and heads, cut LB7 pistons and LBZ rods and a set of caltracs with front QA1 shocks. Would do 12.40s all day long in daily driver trim and drive it all day if needed. Still runs fine to this day, but on close-to-stock tuning and stock suspension.

Fun as hell, wasn't it? Back in the heyday, my car (2-valve 4.6 Mustang) had a little Eaton blower at about 8 pounds of boost, exhaust, OEM Cobra injectors, OEM Focus drop-in fuel pump, and an OEM Lightning MAF. Everything else on the car was bone stock. It ran 12.0s-12.2s in most weather conditions, and would occasionally click off an 11.90 if it was cold outside. I put over 20k miles a year on the car, and I'm not sure I ever drove it without several WOT pulls. Not once did it give a single issue. It was an absolute blast to drive.

Then came time for more boost, and then a built motor, and then a built trans, and then a bigger blower, and then a full fuel system, and then....and then....and then.... It never ended, and every additional mod seemed to bring more problems of some sort (be it durability, noise, fuel mileage, etc.). When I sold it, it was making ~2x the power it was when running low 12s, but not even remotely close to as fun to drive. And as such, I don't think I put 5k miles on it the last 3 years I owned it. I definitely learned a lesson there.

I'd love to get the truck in that same power / reliability territory. I know stock fuel and air will get relatively close to the power goals, but I think the longevity is seriously in question at those levels. Hence my thread here considering what it'd take to get that rock-solid durability. Of course I always have the alternative to just detune it a little and live with low-mid 13s. But heck, that'll barely out run minivans these days. 😅

If your worried about haze with fingers pistons then go with mahle performance cast.Ive did more tune revisions since I put mine in and even got new tunes from a very reputable tuner and I'm still not quite satisfied.They are super strong pistons but for 600hp? Performance cast and run with it.Just my 2 cents

Yea, that's what worries me about the oval-bowls. Seems safe to say that I positively would not break them at 600 rwhp, but I see way more posts from people who say that cleanliness and economy suffers with them, than those who say it doesn't make any difference.

The oil pump is supposed to flow more/more pressure, and the I believe you can use the LML piston squirters that also flow more to help with piston cooling. The newer oil coolers are from the L5P trucks are 15 or 20 row oil cooler vs the 10 row cooler on the 01-15 duramax's.
A new 17-19 oil cooler is cheaper than a new 01-10 oil cooler anyhow. Also a direct replacement with a few longer bolts. I put one on every engine I do.

Learned something new. I may replace the oil cooler anyways at some point, if I'm feeling fiesty / bored. Does the oil pump just bolt-in? Seems Bdsankey below suggests that there may be some machining involved (not an issue seeing that I work in a machine shop, ha).

My LB7 build isn't far off from this concept, except it's power goal is higher.


I personally would do the following for your goals:
-10mm CP3
-SAC65% or SAC100% injectors
-64mm IHI or S475/stock kit (depends how often and how heavy you tow)
-SoCal street rods
-Mahle Motorsport cast pistons without reliefs
-SoCal 3388 cam
-SoCal or Manton valvetrain (springs/pushrods)
-Fluidampr
-BD Flexplate
-Wagler pinned/shimmed LBZ oil pump or machine an LML oil pump to fit then pin/shim it
-Mahle/Clevite "H" bearings
-2020 L5P engine oil cooler
-ARP everywhere (Merchant/ARP rocker shaft bolts also)
-Built trans with Goerend R
-Lift pump of your choice
-Danville/DHD water pump
-LML driver side manifold and 2" OEM manifold replacement up-pipes
-Quality DSP5 file

That seems pretty darn close to what I'm settling on.

Towing heavy (>10000 pounds) is rare, definitely less than 1k miles a year. Towing moderate (3000-7500) is still fairly uncommon, probably 2k-3k miles a year at most. Most of the driving is just for fun, or with a couple dirt bikes in the bed.

I may be misguided, but I'm definitely leaning towards a modded or drop-in IHI. Fewer non-OEM components, less plumbing, retains the water cooling, etc. I know drive pressure and EGTs would suffer, but I'm guessing they'd be manageable on a 450-500 DD tune and a ~350-400 tow tune.

Is there any concern with the Mahle cast pistons not holding up to abuse / being driven hard at 500-600 rwhp? I was thinking I had read some reports of people breaking those at pretty low power levels when towing / abusing them a little, though I do think I remember those were on later engines (not LB7/LLY). And can you get them at higher compression than 16.5? I'd prefer to stay as close to stock as I could on compression ratio to retain efficiency and cleanliness.

Is that small of a cam worth it in a build with fairly modest power goals like this? Or is your thought to put it in to help with efficiency / / drive pressure / EGTs, etc.?
 

OleBlackyLBZ

Active member
May 22, 2020
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I may catch some flak for this but my cousin has the fingers oval pistons and the things I have heard about them causing a truck to haze and smoke more definitely turned out to be true, I don't think the fuel mileage would be quite as good either with that design. The mahle race cast have been proven to hold some serious power and last doing it so unless your going out on a balls to the wall 1000+hp build I would use the race cast. As far as a drop in turbo and egt's you have nothing to worry about at all if you get a good one, It's really really hard to get mine past 1400 degrees on a 575hp tune, you need to stay in it well past 100mph to get it there.
 

Bdsankey

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Learned something new. I may replace the oil cooler anyways at some point, if I'm feeling fiesty / bored. Does the oil pump just bolt-in? Seems Bdsankey below suggests that there may be some machining involved (not an issue seeing that I work in a machine shop, ha).

The LBZ pump is a direct bolt in with absolutely zero modifications required to run it. To use the LML pump you will need to machine the pump body itself or run the LML front cover/accessory drive. The LML pump moves more volume than any of the other pumps available (Melling or GM) and is also very cheap from the dealer. The shaft needs to be cut down and the body/case of the pump needs to be machined for the reluctor wheel. You also will have to cut/grind a rib out of the upper oil pan where the pickup tube is as the LML pickup tube is significantly larger than the 01-10 tube.


Towing heavy (>10000 pounds) is rare, definitely less than 1k miles a year. Towing moderate (3000-7500) is still fairly uncommon, probably 2k-3k miles a year at most. Most of the driving is just for fun, or with a couple dirt bikes in the bed.

I may be misguided, but I'm definitely leaning towards a modded or drop-in IHI. Fewer non-OEM components, less plumbing, retains the water cooling, etc. I know drive pressure and EGTs would suffer, but I'm guessing they'd be manageable on a 450-500 DD tune and a ~350-400 tow tune.

As for turbos, a modified/drop-in IHI would be perfectly fine for your application. The argument I'd make would be if you're consistently towing heavy (10k+) then a 475/stock setup would be my preference as they respond better to towing than modified/drop-in units.


Is there any concern with the Mahle cast pistons not holding up to abuse / being driven hard at 500-600 rwhp? I was thinking I had read some reports of people breaking those at pretty low power levels when towing / abusing them a little, though I do think I remember those were on later engines (not LB7/LLY). And can you get them at higher compression than 16.5? I'd prefer to stay as close to stock as I could on compression ratio to retain efficiency and cleanliness.

Is that small of a cam worth it in a build with fairly modest power goals like this? Or is your thought to put it in to help with efficiency / / drive pressure / EGTs, etc.?

Personally I don't think you'll ever have an issue with the Mahle motorsport race cast piston at your power levels. As for a cam, I think it would not be a bad idea. You will help make the engine more efficient as well as broadening the power curve to an extent.
 

dmax_ty

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Aug 18, 2011
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Utah
Say one had some access to a LML front cover, block, and other parts, could I put LB7 heads on and have all the benefits of the improved rigidity, strength, and improved oiling of the LML while having it work in an older truck?
 

Chevy1925

don't know sh!t about IFS
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Say one had some access to a LML front cover, block, and other parts, could I put LB7 heads on and have all the benefits of the improved rigidity, strength, and improved oiling of the LML while having it work in an older truck?

yes, it would take some tweaks with water pump setup and you loose the strenght of your LB7 pistons though.
 
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dmax_ty

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Would LB7 slugs work in the LML block? I don’t have much confidence in the LML bottom end. Sorry for the de-rail OP.
 

Bdsankey

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Would LB7 slugs work in the LML block? I don’t have much confidence in the LML bottom end. Sorry for the de-rail OP.

At 600whp you’re not going to get any benefit IMO from the LML block but yes, LB7 pistons will fit no problem.

At 600whp the rods in an LB7 are the problem. Swap them out for a better rod (SoCal, Carrillo etc) and you’re in business.


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dmax_ty

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Aug 18, 2011
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That’s the plan, I am looking into the as-forged Wagler rods paired with LB7 pistons. I have no desire to go north of 550HP. The most fun I’ve ever had in my trucks is with the stock charger. I want to keep that as the limiter with a STOUT bottom end. Class 8 trucks have opened my eyes to power and longevity playing nice so I’m hoping to mirror that with a lighter duty diesel.