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Discussion Starter #1
Hey all,

So I was researching what my car originally had with the build sheet and what I have now. The transmission (original serial number), intake, and head numbers look correct. I'm getting mixed results with some websites on the engine. Maybe you all can help. Here's what I have on the 1968 GTO auto 400.

YS Engine (not matching serial but correct year) is casting number 9790071 with a date Sep 27th 1967 (I277). Some sites say 400 HO, others say normal 400 at 350HP. Any idea?

I do have 16 heads dated Nov 1st 1967(RH) and Dec 30 1967(LH) which one place says 2.11/1.77 HO. I also have LH manifold casting 9791637 which I found to be LH 400 D-Port GTO Ram Air 3 manifold. The RH manifold looks the same but no numbers.

Thanks for any help.
 

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Sounds like it could be right. Where exactly are you getting the serial number from on the engine?

(The vin number is stamped down low, next to the outer edge of the timing cover. The number adjacent to the YS code is an engine build sequence number.)

Bear
 

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Discussion Starter #3
Yeah I got the VIN from below, doesn't match the build sheet but same year.
My current engine is a 28R.
2 = pontiac
8 = 1968
R = Arlington, TX

I know it's not original but my question, is my current engine HO or standard 400. Says either one depending on which website you look at. I think the difference is basically 350HP or 360HP right?

BTW I went and got a fire ext today after I read your post about the fire :/
 

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YS for 68 and 69 is the standard 400. It would have come in an automatic transmission car. For 68 it would have had casting #16 heads, carburetor number 7028268, and the 066 cam. The block casting number (on top of the transmission mounting flange down below the passenger side head) would be 9790071. It'll have 2-bolt mains. If you're so inclined, this is an excellent starting point for building a stroker motor. :D

Good job on getting an extinguisher! :cheers

Bear
 

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Discussion Starter #5
Thanks for the info Bear.

I did try the Engine Analyzer Demo and played with the stroker specs. I do intend to rebuild the engine this winter. I like the 461 stroker idea.

I'll make a new post on my engine build when I research more. There's tons of info and I'm learning a lot from the forum.

Thanks.
 
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