Machining Aluminum Block vs Iron Block

[Charles_Colfax]

 
Here's the deal:
 
I've got an iron block LM7 5.3 in my 06 Z71 Suburban.
 
I'm working up a mild performance build/re build for it.
 
Downtime is a concern. So I was considering starting with this short block and building it in the garage before pulling the existing motor and swapping out the externals:
 
http://www.high-performance-engines.com/product-p/sp75.htm
 
I planned on looking for a set of 243 / 799 heads in the junkyard.
 
Then I stumbled across this complete L33 aluminum block 5.3 locally:
 
https://richmond.craigslist.org/pts/d/chevy-53-motor-4l60/6671339517.html
 
It would get me the heads I want, but I will still have to have all the machine work done, buy pistons etc, have them installed...
 
Thoughts?
 
CMC
 
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[Charles_Colfax]

After closer inspection of the pictures, and getting the VIN from the seller, it appears that this is a 4th Gen "LY5" Vortec 5300, not an L33.

Anyone know offhand what heads this would have?

(So much for my easy score of a set of 243/799's?)

He is getting me pics of the block and head casting numbers tomorrow.

CMC

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[Charles_Colfax]

Newp.

The more research I did, the more I found the LY5 will require do far more adapting etc

Did find another L33 that I'm gonna look in to.

CMC

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[swathdiver]

Didn't see this until now.  The LY5 will have the same 243 heads and is an iron block.  The only aluminum 5.3 for your truck is the L33 (2005-2006) which is basically a Gen IV adapted for your GMT800s.  The Gen IV equivalent is the LC9.  All Gen IV 4.8s and 5.3s will have 243/799 heads.  The 4.8s are the LY2 and L20.

[Charles_Colfax]

Didn't see this until now.  The LY5 will have the same 243 heads and is an iron block.  The only aluminum 5.3 for your truck is the L33 (2005-2006) which is basically a Gen IV adapted for your GMT800s.  The Gen IV equivalent is the LC9.  All Gen IV 4.8s and 5.3s will have 243/799 heads.  The 4.8s are the LY2 and L20.

The 243 heads and the fact that it was complete is what had my attention.

But after some more research, since it basically is a Gen4, I figured it would take more adapting than I wanted to deal with considering how many LM7 or L59 iron blocks are out there.

Just need you search for heads now.

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[Charles_Colfax]

Content and questions have been moved to other thread.

We can let this one die...

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