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I was looking for the date of my engine...The block has been decked & there is no stamping left.
The cast number is 3955270 which looks to be a 1969 427.
on the side that this number is on(in the drivers back of the block) there is also "HIPER" "GM" "4" & "CONV 2". also under the casting number is a "P".
Is the "HIPER" mean High performance?
How about the 4 that is under the GM?
What is the "CONV 2" Mean?
& how about the P under the casting number?
Last but not least...Where would I find the date.(there is nothing cast into the back of the block on the passenger side.
Thankyou...Tom
 

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Look on the passenger side of the block, forward of the starter area - date should be cast down there on your block in standard 'Julian' form.
The date should be sometime in the last quarter or so of 1968, but no later than Oct. 68.

The "CONV 2" = conveyor line #2.
Yes, the 'HYPER" is the designation for a block specifically alloyed and modified to be used in some higher output applications.
The "P" is usually interpreted to mean a 'passenger' application v.s. a truck, but there is not hard-fast rule for this ...
The "4" is most likely the casting master number.
 

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The casting number 3955270 blocks are 427 but had a relatively short run - between Aug '68 and early Oct '68. This was a transition block between the 3935439 casting and the 3963512 cast 427's. It was used in both passenger cars and Corvettes.
If the date is not were John indicates to look - also check the long side of the block near the freeze out plug or just to the right of the casting number.
 
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