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I'm the new guy, TIA for understanding my LS shortcomings.
What is this marking?
I own some kind of LS, without removing front support for alternator, etc cannot see front block driver side casting mark.
Also, cannot see passenger side rear block for other casting mark without pulling engine. Seems correct??
But I found this cast mark on the front passenger side of the block, having hard time with google machine & identifying this mark...
I scrubbed with steel wool, red scotch & stainless pad with paint thinner & brake cleaner for a while then rubbed with steel chalk....
is there a better way to get a more clear image of these cast numbers? or can someone assist with identification of this label?
Let me know your thoughts, thanks again
Last edited by cheeseburgercod; Feb 26, 2024 at 08:56 PM.
Reason: rotated pictures for ease of user viewing & input
That is an LS based Iron engine Block. That is the date code when the block was cast. It's very difficult to read though. Looks like 04A but I can't tell the last 2 digits. could be 05...
If that's the case it would be the 4th of January 2005.
thanks for the reply buddy
indeed iron block (magnetic) but agree, numbers hard to depict clearly could last 2 digits be 95 maybe?
that second possible "0" does not look much like the apparent first "0"....thus, do factory casting marks typically have obvious physical & visual variations for identical numbers (in this case "0")or letter shapes within the same cast number?
maybe the block cast tool got worn over time and causes this?
I googled every version of what the 04A## versions could possibly be and found nothing
But I did find out that it is either a 4.8 or 5.3 from a Sierra model truck of some year, it is a 323ci - 706 alum heads and OEM intake manifold
intake manifold is 25321788 which is the black plastic letters SAE PA66 GF33
and appears to have been used in 05-06 Silverado/Sierra model trucks....and it has a Vortec manifold trim cover
the vapor cannister purge solenoid is 12573220 - so could this truck be a 2004-07 model?
guy I purchased from think it was from a 2012, then thought maybe 2001...
but some of the above OEM numbers lend itself to a 04-07 or a 05-06 model truck which would correspond to 04A05 possibly
will just keep digging for what appears to be OEM parts and report back
this is OEM intake plastic lettering this is the vapor cannister solenoid on top of the front of the intake - that model was issues I bleive in 2004-07 Sierra trucks....
It couldn't be 95. That would not correspond to a correct year or even day of the month. Based on what I have seen and when they were cast I would say 05 is likely the most probable. Especially with 706 heads. If you pop the valve cover off, there is a 4 digit date for the head casting. too.
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What is this cast marking? 
