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Discussion Starter #1
I have a 1967 GTO I am restoring but when I started researching the engine the codes are not making sense. The code on the back of the block is located behind the number 8 cyclinder and is 9790079. The code on the front of the block is YU with 0167581 above the two letter code. The heads have a 47 on the center exhaust ports. Can anyone help me sort this out?
 

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Discussion Starter #3
Thats what I was afraid of. I have had the car for over 30 years and always thought the engine was original. Very dissappointed.
 

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What's the 4 character date code on the top rear of the block, near the distributor hole?
Should be one alphabetic followed by three numerics.

Bear
 

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It is very difficult to read but it looks like J148. I believe that means Oct. 14, 1968. Do you guys know if this is the same block that Pontiac used for the 400. I need to decide if I am going to rebuild this or find something else.
 

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Yes it does, Oct 14, 1968 - which makes it a year model 1969 block (the engine plants always started building engines for the "next" model year about halfway through the year).

Unfortunately no, that's not the same block as a 400, the main difference being the bore size. Factory bore size for a 350 is 3.875, a 400 is 4.120. The cylinder walls in the 350 aren't thick enough to permit boring them out to make it a 400.

Look on the bright side though - if it's power you're after, now you've got a clear runway ahead of you because you don't have to dither about whether or not to keep it "all original". Find yourself a good strong 400 block, use a stroker kit to take it out to 461, put on some good aluminum heads and hang on!

Bear
 

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That's what Bear did....and he's running elevens at the track. And terrorizing the heck out of the rest of us poor souls in "stock" GTO's out there!! Seriously, yes, ditch the 350 and get any 400 made from '67 to '73 or so. On the Performance years forums, I've seen correct, complete '67 GTO engines sell for not a bunch....like $2000 or so. Money well spent. If your car is an automatic base car, it'll need a YS coded block. If it's a 4 speed car, it'll need a WT coded block. If it's and original H.O car, YZ and WS codes. You can go on the internet and research Pontiac block codes all day long very easily by simply googling it. You can also find your engine, thanks to the world wide web. If it were me, I'd at least try to find a '67 GTO engine for the car. If that was too much of an ordeal, I'd buy a 400 and build that. It costs just as much to rebuild your 265HP 350 as it does a 360HP 400. Don't waste your resources on the 350, IMo.....
 

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Discussion Starter #9
I'm still early in this project so I think I wait unit I get farther along on the body before I decide what to do with this engine. Thanks for your guys help though. I am sure I'll be back with lots of issues before I am done. I just finished my rotisserie and got the body off the frame.
 
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