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TrailblazerSS
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658 Posts
Discussion Starter #1
Just pulled my 2007 LS2 and it has one 799 head and one 243 head. I know these are the same castings but did GM really mismatch them or did I get hosed?

The motor is supposed to be untouched other than plugs and wires. I read a couple threads from searching that hinted at GM switching casting #'s but the springs/valves are the same. I can't read the barcode stickers as they are faded away.
 

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trailer park living.
TrailblazerSS
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16,328 Posts
I've heard stories of it but never seen it before.

Sent from my SCH-I435 using Tapatalk
 

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TrailblazerSS
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658 Posts
Discussion Starter #3
I've heard stories of it but never seen it before.

Sent from my SCH-I435 using Tapatalk
Now you have :D I'll pull the valve covers and see if everything looks the same. I'm the 2nd owner but the PO is pretty legit and had no reason to lie.

 

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Premium Member
07 TrailblazerSS
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1,554 Posts
Never seen it happen before... maybe the truck had some kind of repair and the first owner just assumed the heads matched.
 

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moar cowbell
Trailblazer
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6,426 Posts
First time I had my transmission out some of the bolt holes had helicoils in them.. I'm the original owner

So yea, I could totally see gm doing that, lol
 

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Premium Member
2008 Trailblazer SS
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2,764 Posts
What was the reason for pulling the motor? Judging just by the outside, that motor needs some love.
 

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TrailblazerSS
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658 Posts
Discussion Starter #8 (Edited)
Has the typical TBSS knock and this filth is typical of motors that see salt/brine roads up here. Salt actually ate the dipstick tube between the manifold openings and started leaking out. Only has 76k on it.

Salt spray up here is like dust in the air and the fan sucks it through the cooling stack and peppers everything. It's horrible.

Two front manifold bolts are broken off as you can see as well.
 

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TrailblazerSS
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658 Posts
Discussion Starter #9
Looks like I just got lied to about prior repairs. One head is clearly newer than the other but it could be a non-issue if the valves/springs are the same in both. Only a teardown will tell.

The 243 head is clean inside, the springs aren't oil stained, and the rockers aren't oil stained. 243 head has a 2006 date stamped valve cover and the 799 had an 07 stamped valve cover.


 

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Premium Member
TrailblazerSS
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1,957 Posts
Don't feel too bad, I leased a 2006 tbss and got rid of it because the stupid bank wouldn't refinance me after my initial lease was up, I had some credit problems after my divorce. So I demoded the truck and put bone stock 5.3 heads on it after pulling my stage 2 243's, lol
 

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08 Black Granite
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4,004 Posts
Best just to replace with AFR or some Mamo magic, just to be on the safe side.
 

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tbss
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485 Posts
I'm the 2nd owner of my truck, when I got the usual knock we tore it down only to find half a pack of smoked pall malls on the vloom. I don't smoke pall malls....
 

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TrailblazerSS
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658 Posts
Discussion Starter #15
I have plenty left in the budget to rebuild this motor and remedy this issue. Hopefully this 799 head isn't too far gone to re-use since they are basically the same casting. Will be getting new springs and seals/guides anyway but might have to add valves to the list now.
 

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TrailblazerSS
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284 Posts
I have seen it plenty. Same head different factory
X2...seen it plenty of times. Never on a TBSS though, only on 07+ nnbs trucks
 
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