help on casting number on a intake

The casting number is 12552138 it looks like and lt4 may be wrong

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Originally Posted by shadowbandit

The casting number is 12552138 it looks like and lt4 may be wrong

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That casting number is for the LT1 manifold. The LT4 won't fit the LT1 heads properly without machining. The LT4 manifold is red, has no egr valve and has added material above the ports.

Dam though I got a lt4 intake

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Originally Posted by lt1-xjs

That casting number is for the LT1 manifold. The LT4 won't fit the LT1 heads properly without machining. The LT4 manifold is red, has no egr valve and has added material above the ports.

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Lt4 manifolds had egr provisions. I had to put block off plates on mine.

Posted from my Rezound

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Originally Posted by Fastbird

Lt4 manifolds had egr provisions. I had to put block off plates on mine.

Posted from my Rezound

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From what I can tell, The early 12550630 production manifold used on the Corvette didn't have the egr. The later 12550631 manifold with the egr was used in the LT4 conversion kits from GM and on the 100 or so LT4 Camaros.