# Engine identification



## Harley123 (Jun 28, 2014)

Hello all, first off I would like to start out by saying I'm new to the GTO forum page and I'm glad to be aboard!
I have recently purchased a 67 GTO that I was told it had a non numbers matching 67 400 in it. I don't believe that to be the case after doing some research
I'm wondering if anyone can help me decipher this mess.
The numbers I have off the block are 
9778789
Date code 1214 (which I know is supposed to start with a letter, but it was on the distributor pad
YF 
059386
In addition it has only 2 freeze plugs per side.
From what I can find the 9778789 makes it either 66 or 65 389, but let's just say I'm reading the the date code wrong and it starts with an I, which makes it sept 21st '64
Also from what I can find they did not manufacture a YF block in any of these years... 
Any help is appreciated! 
Thanks in advance!


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## rickm (Feb 8, 2012)

without checking my old books on the subject, a '65 YF block is a 325 h.p, with a/c automatic bonnevile motor. 10.5 comp. that runs great on highest octane pump gas.


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## Harley123 (Jun 28, 2014)

Would this motor be worth rebuilding? She's pretty wore out. Would it be a good platform to get some kind of performance out of?


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## Roger that (Feb 6, 2010)

It is a 389 built in Sept 1964 for a 1965 year model. I keep track of EUN (Engine unit numbers). In Sept 1964 389's were in the 50,000 range. It's the horse power that rickm mentioned.


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## topfuel67 (Dec 23, 2008)

No, that engine is not worth rebuilding for your car. Pontiac engines are expensive to build. You could find the correct dated 400 for your car and rebuild that. Even if not numbers matching it looks better to have the right motor.


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## Harley123 (Jun 28, 2014)

Thanks for the info guys! Much appreciated


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## rickm (Feb 8, 2012)

I have that motor in my '65. I put an 068 cam in it when it was rebuilt. forged pistons balanced crank hi-volume pump true doubleroller stock valvetrain stock'65 gto dist. n 500cfm afb. it runs beautiful and gets up n goes with the 360 hp. cam.


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