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Identifying LM7


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Old 02-11-2012, 07:03 PM   #1
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I just received a pull-out LS engine for a swap into a '72 Chev. 4WD and wanted to confirm it's a 5.3L LM7 and not a 4.8L. The block casting is 12567393 which is the same for both engines. I have the engine ser. no. but can't find any way to check it. How do I identify it? Thanks in advance for the help!

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Old 02-11-2012, 07:38 PM   #2
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Quote:
Originally Posted by hogpuke View Post
I just received a pull-out LS engine for a swap into a '72 Chev. 4WD and wanted to confirm it's a 5.3L LM7 and not a 4.8L. The block casting is 12567393 which is the same for both engines. I have the engine ser. no. but can't find any way to check it. How do I identify it? Thanks in advance for the help!
I can't find that casting # anywhere. I'd check with a local GM dealership in the parts dept maybe.

_____________________________________________
1979 Monte Carlo with a 400hp+ 350ci.
1983 T10 w/2.8L getting parked till can restore and put a v8 in
1994 Blazer 4dr with the CPI(FOR SALE)
1995 Blazer 4Dr 4X4(FOR SALE)
2002 Trailblazer LT
2007 Envoy Denali

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Old 02-11-2012, 08:25 PM   #3
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Here's one list showing that casting number:
CHEVYTHUNDER III Cylinder Head ID Numbers

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Old 02-11-2012, 08:34 PM   #4
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<<<<---- I don't know where this red maltese cross thingy came from. How do you get rid of it?

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Old 02-11-2012, 08:52 PM   #5
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Quote:
Originally Posted by hogpuke View Post
<<<<---- I don't know where this red maltese cross thingy came from. How do you get rid of it?
I think that is the standard one.

_____________________________________________
1979 Monte Carlo with a 400hp+ 350ci.
1983 T10 w/2.8L getting parked till can restore and put a v8 in
1994 Blazer 4dr with the CPI(FOR SALE)
1995 Blazer 4Dr 4X4(FOR SALE)
2002 Trailblazer LT
2007 Envoy Denali

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Old 02-11-2012, 10:09 PM   #6
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Yo Mammy

YOu say that was a block casting number? Where was the number located?

Maltese cross is standard issue for users that don't select a customer avatar.

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Old 02-12-2012, 01:36 AM   #7
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It's on the pass. side rear of the block above the bell housing.

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Old 02-12-2012, 02:08 AM   #8
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Yo Mammy

Gotcha, I'm on my phone right now, but I'll run it first thin tomorrow morning and let yet know what I find out.

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Old 02-12-2012, 03:13 AM   #9
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Thanks Jake. I appreciate it.

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Old 02-12-2012, 05:21 PM   #10
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Yo Mammy

I found this;

Quote:
LM7 5.3L (322" cid) LR4 4.8L (291" cid)

12551358, 12567392, 1256739

Iron block with 96mm bore, can be bored to 99 mm to create a low cost LS1/LS6 engine
comes up as a 4.8/5.3 iron block. Same block used for both motors. Just depends on the crank and rods.

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Old 02-12-2012, 11:46 PM   #11
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OK Jake. Thanks for checking on it.

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Old 02-12-2012, 11:46 PM   #12
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Yo Mammy

No problem, I wish I could tell you for certain. Did you get heads with it too? Maybe we can check the numbers on there and determine?

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