# Engine Identification 70 GTO



## goatship (Mar 13, 2012)

Hi, I need help and hope there is somebody who really knows 400 engines. I am getting ready to sell my 70 GTO and no matter how much I research it, I can't figure out if the motor was actually built with the car or not. Here is what I have been able to find out: The Casting # is 7970071. The date, by the distributor is 09 with the last # an oversized O. The front date code (wich is the most confusing) 0273569 WT or WZ. I can't see the bottom of the Z (almost like a 7) The manifold dates K198 and K199 with a large 6 and 2 cast into it. With the car being for sale, I'd like to know what to tell perspective buyers about the motor. If anybody knows what I'm looking at, I'd appreciate it.


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## Pontiacpurebrred (Jun 22, 2011)

Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc
1970 400 350 HP WT M 10.25 067 12 1-4 7040263 Block Casting 9799914

No 1970 WZ blocks were made

Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc
1967 400 325 HP WZ M 10.75 067 670 1-4 7027273 Block Casting # 9786133
1968 400 335 HP WZ M 10.75 067 (2)16 1-4 7028265 Block Casting # 9790071
1969 400 330 HP WZ M 10.75 067 62 1-4 7029263 Block Casting # 9790071

Number 62 heads are 1969
Year Engine Hp Code Valve Misc
1969 400 330,335,350,366HP 62,48(MT) 2.11/1.77 72cc
1969 400 340HP(GP) 62 2.11/1.77 72 cc

My guess from what you provided is that you have 
1969 400 330 HP WZ M 10.75 067 62 1-4 7029263 Block Casting # 9790071

Hope that helps.


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## goatship (Mar 13, 2012)

Thanks for the great info, it does help.I was told by previous owner that had the car many years(from mid 70's) that was the original engine. I was hoping to verifiy that.
I'm not sure if there is a way to do that. The numbers you gave do match carb,trans.
I never used PHS so I'm not sure how far they can get into it. Thanks again for the help.


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## BearGFR (Aug 25, 2008)

There is a way to verify.

There's a second set of digits stamped into the front of the engine, down low on the passenger side, next to the timing cover (a few inches -below- where you found the WT stamp). They're stamped "veritcal" (they run up and down instead of side to side). These digits will match the serial number portion of your VIN if it's the original block.

(see the attached photo)

Bear


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## Hootchi (Apr 7, 2021)

Thanks Bear GFR, I have a 68 GTO and Im having a hell of a time trying to find the stamp. Do the covers have to be off to find this vertical stamp? Also, I was told that mine is NOT numbers matching so once I get the number how do I find the details on this motor based on that number?


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## O52 (Jan 27, 2019)

Sometimes the vertical VIN stamp will be found halfway between the timing cover and the cylinder head, primarily on the Fremont cars/engines.


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## Hootchi (Apr 7, 2021)

O52 said:


> Sometimes the vertical VIN stamp will be found halfway between the timing cover and the cylinder head, primarily on the Fremont cars/engines.


Found it thanks....now to track down what it is.....687395 YS


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## O52 (Jan 27, 2019)

Thats the Engine Unit Number or EUN. That number was stamped at the engine plant in Pontiac, MI and was used by Pontiac for inventory (parts) and warranty control. It's a consecutive number for all V8s built during the model year. Depending on the year, 687395 could be a April/May engine build followed by the car one to six weeks later on average.

In the photo below I highlighted with an arrow where the VIN would be located. As I mentioned earlier a number of engines installed at the Fremont factory could have the VIN stamped in the circled area. If there isn't any VIN you could have a late 67 block which would correspond to the EUN number. Look for the date by the distributor hole. Should be a letter/three number code such as these examples D108 (Apr 10, 68).


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## Montreux (Mar 8, 2009)

BearGFR said:


> There is a way to verify.
> 
> There's a second set of digits stamped into the front of the engine, down low on the passenger side, next to the timing cover (a few inches -below- where you found the WT stamp). They're stamped "veritcal" (they run up and down instead of side to side). These digits will match the serial number portion of your VIN if it's the original block.
> 
> ...


Hey Bear—
I think your illustration is a little misleading. 

The number identified as “65 and up”, located under the passenger head, is the Engine Unit Number (EUN). This is a serial number and will appear on the PHS, but is not the VIN. The two-letter code is the engine code that will tell power level and transmission, but is NOT year specific. YS engine code is used for many years. 

The number identified as “1967 and later” IS a partial VIN number; however, it was NOT used in 1967. It may have started in 1968.

The only reliable way to verify YEAR and DISPLACEMENT is the engine casting number. The casting number is located on the top rear of the engine, and should be visible with the engine in the frame. For 1967, this number is located near the distributor, and part of the number may be machined away. Later engines have the casting number behind the passenger side head. 

Late engines (75-77 or later) are not strictly year-specific; some engine casting numbers may span several years. I think they cast large lots, and used them until they were gone. 

Once the year and displacement are established by the engine casting number, the two-letter engine code will tell the original hp and application. (2 barrel, 4 barrel, 3-2’s, auto or manual, A-body, F-body, big car, HP rating).


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## Hootchi (Apr 7, 2021)

Okay, after more searching I think I finally have it. Looks like R305062 with the other number being the 687395 YS, Can anyone tell me about this engine? I am the 4th owner, and have had the car for 20 years. The third owner did the previous restoration and told me the engine comes from a different 68 GTO what was crushed in a barn accident(?). So, IM trying to see what the deal is.


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