LLY: Where To Draw The Line? - Actual Experiences Wanted

carter_44

...
May 11, 2010
575
0
0
AZ
I just turned over 206,000 miles tonight. Stock motor with studs and a S366 and 30% over injectors. I drive it to work every day and have towed heavy multiple times no problem. I think its a very good combo if you want more than tuning but dont want to have to build the motor.

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I've seen many a stock engine, stock fuel, s366 truck bend rods. You're on borrowed time. That is definately not a stock engine safe setup.
 

SwitchBack

New member
Sep 8, 2012
307
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Vermont
I've had fully built trucks to bone stock and quite a few in between. Honestly built trans stock turbo and fuel is a fun truck and damn reliable. I'm kind of at the point that I'm sick of projects though so it could be that part of me talking.
 

carter_44

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May 11, 2010
575
0
0
AZ
Its only been this way for 4 years and like 60k miles. I dont think that qualifies as borrowed time
I was well below your power level and this was the result. Just sayin.

Not to mention those LB7 rods will generally handle less power than my LBZ pistons before failure.
 

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Bustedknuckles

Honey Badger
Sep 25, 2010
1,308
2
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Hagerstown MD
I was well below your power level and this was the result. Just sayin.

Not to mention those LB7 rods will generally handle less power than my LBZ pistons before failure.
Its all in the tuning imo. You shouldn't have cracked a piston with less power than me!

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OregonDMAX

NOT IN OREGON, NO DURAMAX
Apr 28, 2013
3,964
8
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Goodyear, AZ
Not to mention those LB7 rods will generally handle less power than my LBZ pistons before failure.

I don't agree with that, you look at one of those pistons wrong and get a hole in it. Lb7 rods bend with too much power but the lbz pistons fail at random times with too many variables other than just too much power
 

Cknight199

New member
Aug 23, 2012
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Salt Lake City, Utah
I don't agree with that, you look at one of those pistons wrong and get a hole in it. Lb7 rods bend with too much power but the lbz pistons fail at random times with too many variables other than just too much power



X2. Imho you can make an lb7 and lly live at high hp with a large single and less torque. Lbz Pistons are a crap shoot as to what they will hold.

My .02 after building my motor... if I were to do it again I would have just kept my lbz crew cab as a stock motor built trans truck, and get a cheap lb7 single cab to go real fast for cheap.

I daily drive my truck with a built motor, but it is high maintenance. Plus once you get to a certain point, you will be wanting a tow truck and trailer to take it to events just in case something breaks... I ran into this last weekend.


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04LB7yz

New member
Aug 16, 2013
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Way North Minnesota
The way i look at a build is this... Once your in there putting rods in you might as well do pistons, once your doing those you might as well add a cam, now that you added a cam valve springs and push rods get added, now your in this deep you should probably put billet mains and a girdle in, and the list goes on and on.. Then by the time your done you have a motor good for 2000HP that you put every penny you had into and a truck that will bring 25G's at best... I know you'll never make money on it but when you actually look at build prices its mind boggling... And if you do have the self control to only put rods in it, then 6 months down the road you'll be pissed you didn't do the rest...
 

Brshan01

New member
Aug 19, 2013
55
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Zimmerman, MN
I regret taking my LML beyond the CP3 and deletes. At that point the truck was happy, everything worked as it should.

I put in an s475 compound kit, probably had about 1yr (under 25k on it) lifted the heads. At that point I decided to change it up with a s369 single with 40% over injectors (already had a 10mm cp3 in it), it ran maybe another 4k miles before it lost 4 pistons. Its been in the shop since July for a motor build. Makes me sick to my stomach thinking about how much I have invested in this truck, I could have 2 LML's if I would have left it stock.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,670
5,818
113
Phoenix Az
The way i look at a build is this... Once your in there putting rods in you might as well do pistons, once your doing those you might as well add a cam, now that you added a cam valve springs and push rods get added, now your in this deep you should probably put billet mains and a girdle in, and the list goes on and on.. Then by the time your done you have a motor good for 2000HP that you put every penny you had into and a truck that will bring 25G's at best... I know you'll never make money on it but when you actually look at build prices its mind boggling... And if you do have the self control to only put rods in it, then 6 months down the road you'll be pissed you didn't do the rest...

if your doing that, you need to look at the bigger picture and not just striving for the HP number.

its all about building it with a little common sense. your not going to get 1000rwhp to the ground on the street without 4wd. its going to be smokey before spool up cause you have large chargers to clean the fuel up for the HP or its going to be smokey cause your pushing the quick spooling chargers hard to get that hp.

you also have drivetrain to contend with as well and whats going to last. trans will need a refresh every year or 2 depending on your driving style. axle wrap bars will be needed at min. making sure your front end is always tight so you can use 4wd to put that power to the ground. adjusting ride height to work around 4wd. making sure boost leaks arent an issue. keeping trans cool. and on and on.

this is all just based on 1000rwhp truck. you cant look at resale value on these if you are wanting to build the engine. its like buying a new truck and being so worried about the depreciating value the moment you drive it off the lot. your doing it cause its what you want.

built engines can be reliable if your smart with what your doing. you start pushing the limit of things and you better be prepared for issues. you keep all things within their limits, make sure parts are up to snuff and put that engine together correctly, you wont have issues.
 

04LB7yz

New member
Aug 16, 2013
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Way North Minnesota
if your doing that, you need to look at the bigger picture and not just striving for the HP number.

its all about building it with a little common sense. your not going to get 1000rwhp to the ground on the street without 4wd. its going to be smokey before spool up cause you have large chargers to clean the fuel up for the HP or its going to be smokey cause your pushing the quick spooling chargers hard to get that hp.

you also have drivetrain to contend with as well and whats going to last. trans will need a refresh every year or 2 depending on your driving style. axle wrap bars will be needed at min. making sure your front end is always tight so you can use 4wd to put that power to the ground. adjusting ride height to work around 4wd. making sure boost leaks arent an issue. keeping trans cool. and on and on.

this is all just based on 1000rwhp truck. you cant look at resale value on these if you are wanting to build the engine. its like buying a new truck and being so worried about the depreciating value the moment you drive it off the lot. your doing it cause its what you want.

built engines can be reliable if your smart with what your doing. you start pushing the limit of things and you better be prepared for issues. you keep all things within their limits, make sure parts are up to snuff and put that engine together correctly, you wont have issues.

This is exactly what I was getting at as far as spiraling out of control. I am by no means saying that I want 2000HP I was just generalizing all of those things as being might as wells and if you don't they'll turn into should haves down the road.

I am know expert but from what I have learned on this forum and personal experiences. Once these trucks get brought past stock fuel and air. Everything is pushed to its limit. So in order to make let say a reliable 800HP you need the supporting mods for the possibility to make over 1000HP. Then if you have the capability to push 1000HP you will do it. Maybe not right away but you will. And that's when the destruction of parts and your wallet really begins... I guess it really all boils down to self control..
 

S Phinney

Active member
Aug 15, 2008
4,008
18
28
Quncy, Fl
I regret taking my LML beyond the CP3 and deletes. At that point the truck was happy, everything worked as it should.



I put in an s475 compound kit, probably had about 1yr (under 25k on it) lifted the heads. At that point I decided to change it up with a s369 single with 40% over injectors (already had a 10mm cp3 in it), it ran maybe another 4k miles before it lost 4 pistons. Its been in the shop since July for a motor build. Makes me sick to my stomach thinking about how much I have invested in this truck, I could have 2 LML's if I would have left it stock.



How did it run with the twins versus the 369?


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04LB7yz

New member
Aug 16, 2013
120
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Way North Minnesota
So its looking like I am going to do a mild build to my truck I am looking for 650-750HP relatively reliable. :woott:

I'm buying a 10mm pump and head studs from clrussel. :thumb: Then the plan will be to start stacking parts on the shelf until i am ready for the build. Here's what I am thinking...

Carrillos or crowers
Keyed crank and cam
New bearings throughout
Port/polish heads - valve job guides and seats
60 over sticks
Danville 68stg2r
Manifolds and up pipes
Intercooler tubes


Is there anything that I don't have listed that is a must? Will my pistons be on borrowed time?

Also my tranny does not have any shiny billet inside, is this necessary for my goal?
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,670
5,818
113
Phoenix Az
So its looking like I am going to do a mild build to my truck I am looking for 650-750HP relatively reliable. :woott:

I'm buying a 10mm pump and head studs from clrussel. :thumb: Then the plan will be to start stacking parts on the shelf until i am ready for the build. Here's what I am thinking...

Carrillos or crowers
Keyed crank and cam
New bearings throughout
Port/polish heads - valve job guides and seats
60 over sticks
Danville 68stg2r
Manifolds and up pipes
Intercooler tubes


Is there anything that I don't have listed that is a must? Will my pistons be on borrowed time?

Also my tranny does not have any shiny billet inside, is this necessary for my goal?

you should delip the pistons and then at minimal, cut them down the amount you deck the block. you should keep an idea of piston to head clearance you want and adjust the piston height according to that. most guys like a .030 clearance if you run it hard (at or above that 750 mark). i like a little tighter for little better fuel econ but i also run around at 600hp 99% of the time. the very few times i ramp up to 800 is just for drag racing purposes.

trans is all dependent on how well the parts were heat treated from factory. they could hold up just fine if you have good tuning with no tie ups or they could snap the instant you have a little tie up cause tuning wasn't quite right yet or the trans had not fully learned. your in the grey area there. most shops recommend beyond 600hp
 

04LB7yz

New member
Aug 16, 2013
120
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Way North Minnesota
Okay after seriously talking with my father about doing the machine work he basically told me that I am insane and that he wouldn't do it for me. So after fighting with him about it for over an hour I leveled with him and decided to listen to him... His advice was to spend my money on my toys and to keep the truck to haul my toys. Because if my truck doesn't work I cant take my toys anywhere to play with them. So maybe someday ill get my built duramax but not this go around... Dads and their logic...:roflmao:

So now I have a few other questions.

I still need to do the heads so they will get rebuilt and ported and polished by the old man... Studs will also be added.

I have already bought the 10mm pump so that's going in at that time also. My plan was to do 60 overs but if the bottom end isn't coming apart I think maybe i should go for smaller ones? Or should i just keep them stock with the big pump?

As for the turbo I would like to do something there, but I am kind of hung up on where to go. I like the idea of the drop in 68stg2r and have heard tons of good things on them. But will this be to much for my application? I would also like to do cold side hot side and y bridge and after looking into it I think a twin kit with a cast s475 is actually cheaper in the long run if the y bridge and intercooler tubes are added.. But from what i understand twin setups make short work of stock bottom ends. I am not looking for perfect reliability but i would like to make the right decisions to keep it alive as long as possible. :thumb:
 

Dozerboy

Well-known member
Jun 23, 2009
4,892
470
83
TX of course
Pick what you want and a good tuner will put it al a power level to make it survive. I would just stick with the stock injectors for now, but 60 overs can be tuned to be safe.


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TROJAN366

Gold Rush
Jan 13, 2012
2,474
1
38
MASS
40-60 overs dialed way back might not be a bad idea. Good tuning will allow you to pull pulse width and timing and hopefully help keep the pistons happier longer. That 68R with that fueling would be a blast to driver.