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I have a Pontiac engine (in a car) with Edelbrock heads on it. Without removing the heads, I'm trying to figure out what block this is...

Block casting date code is I108 (September 10th, 1968, which makes it a block for a 1969 production car).
Casting number is 9792968, which can be a '69 428 or a '69 Ram Air V 400
Block ID code stamped into the front of the block is "XP," which would designate it as a Ram Air IV 400. There is no indication or marking to indicate that it has been altered. This does not jive with the casting number.

I don't want to remove the heads to check the bore diameter. Has anyone had actual and factual experience with this ID code/casting number combo and can say for sure what this is..?

Thanks!!
Lars
 

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You're correct about it being a model year '69 block. You sure that engine stamp is XP and not XF? Look closely. I'm betting it's XF, and that it's a '69 428.
Just a guess though, based on what's the most likely scenario.

Bear
 

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That's a good, logical suggestion... I'll have to do a little paint scraping to see if it's possibly an "F," but it's sure looking like a "P." A closer, critical examination is in order.... I'll post results... Thanks for the good suggestion!
Lars
 

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No block size cast in it? I read that 428 was being cast on the block in late '68 for the '69 engines.

428 will have the pyramid transfer lug on the back of the block.
 

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I thought the RAIV block had the last number of the casting hand stamped into it. I have a 1970 RAIV block and that’s what it has
 

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What code heads are on the engine, also if the intake is off you may see some numbers in the center lifter valley to indicate what it is.
My 2 Cents :)

Some definitely did have the last digit ground off an restamped, but I'm not sure if we can say that they all did.
I have a Pontiac engine (in a car) with Edelbrock heads on it. Without removing the heads, I'm trying to figure out what block this is...

Block casting date code is I108 (September 10th, 1968, which makes it a block for a 1969 production car).
Casting number is 9792968, which can be a '69 428 or a '69 Ram Air V 400
Block ID code stamped into the front of the block is "XP," which would designate it as a Ram Air IV 400. There is no indication or marking to indicate that it has been altered. This does not jive with the casting number.

I don't want to remove the heads to check the bore diameter. Has anyone had actual and factual experience with this ID code/casting number combo and can say for sure what this is..?

Thanks!!
Lars
I have a Pontiac engine (in a car) with Edelbrock heads on it. Without removing the heads, I'm trying to figure out what block this is...

Block casting date code is I108 (September 10th, 1968, which makes it a block for a 1969 production car).
Casting number is 9792968, which can be a '69 428 or a '69 Ram Air V 400
Block ID code stamped into the front of the block is "XP," which would designate it as a Ram Air IV 400. There is no indication or marking to indicate that it has been altered. This does not jive with the casting number.

I don't want to remove the heads to check the bore diameter. Has anyone had actual and factual experience with this ID code/casting number combo and can say for sure what this is..?

Thanks!!
Lars
 

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Lars, Have you come up with anything definite on this engine? All the numbes and letters sound alot like a 428 in my garage. Thanks for letting us know.
 
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