best block

ncdmax03

Member
Nov 4, 2012
125
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18
I was wondering what would be the best block for a motor build? ive got an lb7 and an lbz which would be the better of the two
 

LWATSON

future trans limpers
Jul 30, 2008
2,587
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Scotland Neck NC
I've heard of some LBZ blocks with cracked cylinders here lately, I'm using an LB7 in my build. The LBZ blocks are suppose to be stronger but the most powerful dmaxs out there have LB7 blocks. LB7 and LLY's use the same block.
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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ZEPHYRHILLS, FL
Isn't the LML the best of the stock blocks? I was under the understanding that the blocks from 01-10 were all about the same for strength, but heat cycles can take a number on them.
 

dmaxbowtie

Duramax fiend
Jun 2, 2011
228
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RI
Did you ever get solid info on this? I'm curious to know the differences (if any) in each different generation block.
 

LWATSON

future trans limpers
Jul 30, 2008
2,587
1
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55
Scotland Neck NC
I believe 01-05 are the same LB7 and LLY. Then 06-10 LBZ and LMM are the same. Then the new LML in 11 and 12 I dont know if there were any block changes for 13.
 

dmaxbowtie

Duramax fiend
Jun 2, 2011
228
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16
RI
But what are the differences? Could I put an lb7 crankshaft in an lbz block? Are they all interchangeable?
 

dmaxbowtie

Duramax fiend
Jun 2, 2011
228
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16
RI
Ok, thanks. Does anyone know any more details on the differences of the actual blocks? Maybe different metals or different fastener threads or anything?
 

sickdiesel

New member
Apr 22, 2010
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we use a lbz block in maxd out. My blackout has an LBZ block but the new motor im doing is using a LLY block.


LBZ/LMM are "supposed" to be stronger..
 

ripmf666

Active member
Sep 20, 2006
15,123
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Wentzville Mo
The LBZ blocks have more webbing around the mains and the threads for the main bolts are deeper. I think I posted all the changes that Gm did in the Gm spec area for each year.
 

ripmf666

Active member
Sep 20, 2006
15,123
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Wentzville Mo
I've heard of some LBZ blocks with cracked cylinders here lately, I'm using an LB7 in my build. The LBZ blocks are suppose to be stronger but the most powerful dmaxs out there have LB7 blocks. LB7 and LLY's use the same block.

We're are you hearing all of this at ? If you don't trust that Lbz block I take it will be for sale?
 

LWATSON

future trans limpers
Jul 30, 2008
2,587
1
36
55
Scotland Neck NC
The guy that is going to build my block said although its not an epidimic "spelling" he has seen a few LBZ blocks with cracks in a cylinder. The cracks were perpindicular to the bore not up and down the length. He claimed to have never seen an LB7 do this. And yes the LBZ block will be for sale that is in my truck, It's going to be a while before its swaped out but I'll send you a PM with details once its out.