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Hello I am new to the forums and appreciate any help.

My father bought a 69 convertible GTO RA4 just before I was born and I have been helping him search for a matching engine (original is long gone) most of my life. I am in my 40s now and been kinda taking this on myself to keep looking. I recently found a 70 marked WW but the casting number is just throwing me for a loop. My father is asking his old Pontiac parts dealer if it makes any sense but he also suggested I reach out to a community for possible answers.

As far as I can tell it is the Tempest parts number from the catalogue
"Block assembly 479879" 1970/RAM AIR IV-CODED-XP-OR-WW
http://wildaboutcarsonline.com/members/AardvarkPublisherAttachments/9990412175418/1969-1974_Pontiac_Parts_Catalog_Grp_00_Parts.pdf

Is this possibly some kind of replacement block?


Thank you again,
Jason
 

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Not sure who has this for sale, but can easily state someone with questionable intentions had "some fun" with a grinder & set of stamps.

an original '70 WW or XP block would have a 979991(5) casting number. Both '70 RAIV GTO's & the 88 RAIV TransAms used these two codes, XP & WW. At the Pontiac engine plant, the last digit of a 9799914 400 block was ground off & a correct font 5 was stamped. A few original '70 WS blocks were also assembled on the 979991(5) casting block instead of normal use of 4 bolt main capped 9799914 casting block. Have owned several SR fitted "915" casting blocks, & have several friends that have documented SR fitted blocks in their cars, along with original dealership & zone paperwork

A SR 400 block cast for '70 model applications during the '70 model year would simply have a 979991(5) casting block with an SR8xxxx stamped near the timing cover area on the face of the block. Once the 481988 casting 400 blocks began being cast in late July of '70, all of the casting number was removed smoothly, & for a fitted 4 bolt main block, the entire 9799915 casting number was stamped with the correct font stamps. Whoever went to some trouble to fake the above block seems to not know hosnway around these SR blocks as far as how they were stamped. He also seems to have used some form of gangstamper on the assembly number & on their attempt to stamp the part number out of the Pontiac Master Parts books instead of correct application casting number.

SR 400 2 bolt main blocks for '67-69 usage & built as SR blocks during the '70 model year were stamped with the earlier casting number 9790071. More on the earlier SR 400 blocks:http://www.gtoforum.com/f83/1969-gto-conv-4-spd-saved-woods-111825/index2.html#post760297
 
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