# Engine Code X4???



## Lukeduk1980 (Jun 22, 2009)

Hey Guys, I just found my dad an original 1968 GTO with supposely matching numbers on the engine, however, the numbers don't make sense. The engine serial number says: 663347 and underneith it says X4. I do not show a listing in GTO Alley or anywhere that says X4? I believe it is a 400 cidand the car has the ram air intake but has caps over it that are removable. It looks like that are bolted in. Can anyone give me some info on this GTO motor? Thanks in advance.

Lucas:shutme


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## auburnconsulting (Nov 3, 2008)

pics of caps?


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## Lukeduk1980 (Jun 22, 2009)

*Caps (Kinda)*

front end on Flickr - Photo Sharing!


If you look at the hood, you can see the that the ram air intake has these "caps" over there and the air doesn't go completely in.

Lucas:shutme


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## 68greengoat (Sep 15, 2005)

Here's all the X4 coded blocks. You'll need to find the year and/or block casting number of your block to determine the specifics. If it's an X4, it's not a numbers matching block as you can see below... X4's were used during '73, '76 and '79 years. Are you sure it has the ram air components under the hood? Your pic looks like a ram air hood with closed non-funtioning scoops. 

X4 A-body 73 400 185 Turbo 400 L-65 P 1x2 481988 2 
X4 A-body 76 400 170 Turbo 350 L-65 N 1x2 500557 2 
X4 A-body 79 301 150 Turbo 350 L-37 U 1x4 525934 2 
X4 B-body 73 400 185 Turbo 400 L-65 P 1x2 481988 2 
X4 B-body 76 400 170 Turbo 350 L-65 N 1x2 500557 2 
X4 B-body 76 400 170 Turbo 350 L-65 N 1x2 500557 2 
X4 B-body 79 301 150 Turbo 350 L-37 U 1x4 525934 2 
X4 B-body 79 301 150 Turbo 350 L-37 U 1x4 525934 2 
X4 F-body 73 400 185 Turbo 400 L-65 P 1x2 481988 2 
X4 F-body 79 301 150 Turbo 350 L-37 U 1x4 525934 2


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## Lukeduk1980 (Jun 22, 2009)

From what we know, this car has been in storage for 17 years. Luckly, the car was stored in an enclosed garage and was away from most of the elements. The engine is painted like a blue green paintandalso looks like a 400 cid. What is the difference between a non-functioning ram air intake and a real ram air intake? Got a few pictures to show me the difference, I will also post some more pictures of the block and hood later today.

Lucas:shutme


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## 68greengoat (Sep 15, 2005)

When you open the hood you would need to see these 2 pieces along with a carb and hood seal. The first one bolts to the underside of your hood and the second goes around your carb. You may also have moveable flappers(3rd pic) in your scoops that would be controlled by a pull cable under the dash. In '68, the scoops were left open with no flappers. Someone could have converted the scoops like a '69 if you have moveable flappers.


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## Lukeduk1980 (Jun 22, 2009)

Definately not ram air on mine then. OK. Well, i am on my way to take pictures of the car and closeups of the engine serial and date information. I'll also try to get the engine casting numbers as well.

Lucas :shutme


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## Lukeduk1980 (Jun 22, 2009)

*Engine Serial*

OK, the Date Code says D053 and the engine is 663347 with the X4 underneith it. 

GTO on Flickr - Photo Sharing!

Here is the Engine date code (D053)

GTO on Flickr - Photo Sharing!

And here is what the inside of the hood looks like:
GTO on Flickr - Photo Sharing!

What can you tell me about the motor? and hood? What is the horsepower rating? Vehicle has orginial 400 Turbo hydromatic auto transmission.

Lucas:shutme


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## 68greengoat (Sep 15, 2005)

Date code = April 5th 1973. Your motor is out of a '73. 663347 is the serial#, basically means nothing. Here's the breakdown of the motor:
X4 A-body 73 400 185 Turbo 400 L-65 P 1x2 481988 2
X4 - engine code, A-body car(used as and example. Possibly it came out of a B or F body), 73 - year, 400CI, 185HP, Turbo 400 tranny, 1x2 - 2 barrel carb, 481988 - block casting# located behind the #8 cylinder next to the firewall, 2 - 2 bolt mains.

Hood is a standard GTO hood without ram air. You can see on the bottom side of the hood where the upper ram air pan would bolt in.

Get yourself the PHS documentation( PHS Historic Services ) for that car. Alll you have to supply is the V.I.N. number. The doc will tell you exactly what it looked like and all the options it had when it rolled off the assembly line...


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## Lukeduk1980 (Jun 22, 2009)

*Thanks man*

Thank you, i will definately go through that service to get the options for the car. 185 HP seems alittle low for that car since the standard 400 in 1968 was around 350 HP. What typically was the F or B bodies made for 1973? also, is the vin stamped on the front of the vehicle that that motor originally came out of? just underneith of the water pump or something? 
Also the transmission number is PX-68-44932. Anything you can tell me about that?

Thanks again for everything

Lucas:shutme


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## Lukeduk1980 (Jun 22, 2009)

Also the heads shows the following casting date (1 (or I) 021) does this make any sense beign that the motor is a 1973?


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## 68greengoat (Sep 15, 2005)

185hp is a little light. But don't forget, it's a '73 not a '68 motor. Hp ratings dropped wayoff in the 70's. I believe they peaked in 1970. B bodies are your Gran Prix's, Bonnevilles etc..... F bodies are Firebird, Trans Am..... The engine V.I.N. code is located below. Passenger side of the timing cover. As you know the cars V.I.N. is located top of dash next to windsheild on the drivers side. Forgive me if that was an obvious comment. Just making sure...

I can't decode tranny's. Judging by the -68- I would say it's a '68. Someone can correct me if I'm wrong....

Good luck... Looks like you have a nice car. I thought I saw factory air in it too!!


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## BobG (Dec 20, 2006)

Lukeduk1980 said:


> Thank you, i will definately go through that service to get the options for the car. 185 HP seems alittle low for that car since the standard 400 in 1968 was around 350 HP. What typically was the F or B bodies made for 1973? also, is the vin stamped on the front of the vehicle that that motor originally came out of? just underneith of the water pump or something?
> Also the transmission number is PX-68-44932. Anything you can tell me about that?
> 
> Thanks again for everything
> ...



Couple of reasons for the difference. after 1970, Pontiac dropped the compression ratio to around 8.5:1 or so, plus, after 1970, all carmakers shifted from reporting SAE gross HP for their HP ratings to SAE net. HTH.


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## 68greengoat (Sep 15, 2005)

The engines VIN will tell you, using the example in the pic 22P361206. 2 = Pontiac, 2 = year '72(3 in your case for '73), P - assembly plant and the last 6 digits would match the last 6 digits of the cars vin which they wont in your case.


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## 68greengoat (Sep 15, 2005)

Lukeduk1980 said:


> Also the heads shows the following casting date (1 (or I) 021) does this make any sense beign that the motor is a 1973?



Probably an "I". Sept 2nd, 1971. Guessing the heads did not originally come with that motor. Somebody probably swapped them out at one point. Although, with '71 heads you could have better compression.


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## Lukeduk1980 (Jun 22, 2009)

Would you believe we bought the car on Sunday (6-21-09) for $1000. Good news is that the guy bought the car in 1995 and drove it for 2 weeks and parked it in a garage and it's been sitting there since. Floorboards look like they've never seen a winter, drivers side has some surface, passenger side is perfect with no signs of surface rust even. Car doesn't run right now as there is no battery in it. The guy we bought it from has fallen on bad times and is moving in less then 2 weeks and had to sell it and quick. My dad just came back from a union meeting basically tell him they the a vote passed and his employers are not closing the doors but he is taking a wage cut and 10% pension plan cut as well, but he could not pass up a deal like this. He bought it and we towed it to his house, 6 miles away. Now we are figuring out how to drain the motor oil and clean the pan without pulling the motor out so we can drop the pan on it. Im guess $200 and it will run like new. 137,000 miles on it plus we were told that the motor was rebuilt just before it was stored for 15 years. Not Bad huh?


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## Lukeduk1980 (Jun 22, 2009)

Yeah, thanks again you guys for all the information on that. I'll keep ya posted on what I find. Also the car has power windows. Which is weird since I thought they did not think they came as an option for that vehicle or year!


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## 68greengoat (Sep 15, 2005)

What's the casting number on the heads? Located on the center exhaust ports. 96, 98 99? Or, something like that...


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## 68greengoat (Sep 15, 2005)

Lukeduk1980 said:


> Yeah, thanks again you guys for all the information on that. I'll keep ya posted on what I find. Also the car has power windows. Which is weird since I thought they did not think they came as an option for that vehicle or year!



Sure did!!


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## 68greengoat (Sep 15, 2005)

Lukeduk1980 said:


> Would you believe we bought the car on Sunday (6-21-09) for $1000. Good news is that the guy bought the car in 1995 and drove it for 2 weeks and parked it in a garage and it's been sitting there since. Floorboards look like they've never seen a winter, drivers side has some surface, passenger side is perfect with no signs of surface rust even. Car doesn't run right now as there is no battery in it. The guy we bought it from has fallen on bad times and is moving in less then 2 weeks and had to sell it and quick. My dad just came back from a union meeting basically tell him they the a vote passed and his employers are not closing the doors but he is taking a wage cut and 10% pension plan cut as well, but he could not pass up a deal like this. He bought it and we towed it to his house, 6 miles away. Now we are figuring out how to drain the motor oil and clean the pan without pulling the motor out so we can drop the pan on it. Im guess $200 and it will run like new. 137,000 miles on it plus we were told that the motor was rebuilt just before it was stored for 15 years. Not Bad huh?


Great find! Congrats!!


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## Lukeduk1980 (Jun 22, 2009)

The center exhaust code says 7K3 on it. The orginial VIN on the engine says 23X177653. Stamping number on the engine block says 481988. does this look right?

Lucas


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## 68greengoat (Sep 15, 2005)

Lukeduk1980 said:


> The center exhaust code says 7K3 on it. The orginial VIN on the engine says 23X177653. Stamping number on the engine block says 481988. does this look right?
> 
> Lucas


Here's the only 7k3 head that I can see:

1972 400 250HP 7k3 2.11/1.77 96cc

If your date code is on the heads is I021, Sept 02 1971, those heads were probably put in a '72 hence the 1972 above. Unless there was a mistake with the chart. At any rate, they only made one head with the 7k3 casting. If you noticed, the HP just went up by having a little better head, higher compression!
The VIN on the engine looks right. The "3" for 1973. And the 481988 is correct for a '73 also. Heads were just changed at some point.


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## Lukeduk1980 (Jun 22, 2009)

What does the X stand for on the engine block? does it give us any insight to what model vehicle it came out of? Also, i was doing alittle research and saw one guy pull the build sheet out from between the gas tank and the truck floorboard of the vehicle. is that common? Would I find mine there possibly? 

Also you staterd that PHS service. Have you used it before? how accurate are they and are they worth it? They also mentioned something about laminating the orginial reproduction window sales sheet. Is it for a typical GTO or for everything that went on that car with that VIN? Just wanted some feedback before I spend $100 on this. 

Another heads up. i got information on the owner previous from the owner that I bought it from. He lives just 40 miles north of me. I could check to se if some miracle he has the original block. I'll keep the posts.

Lucas:shutme


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## Rukee (Feb 8, 2007)

Some of the build sheet hae been found there, or under the back seat, or stuffed into the springs of the base of the front seats.
PHS is absolutly worth it, they will tell you every option your car came with from the factory as ordered and even send a copy of the factory build sheet as it came down the assembly line.


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## 68greengoat (Sep 15, 2005)

No idea what the "x" stands for on the engine code. I think it was just a letter designation generated by pontiac. All GTO's engine codes started with an W, X, Y or Z. Except for '64. They had 76, 77, 78 or 79. None had the X4 unfortunately. No biggy tho.

Rukee is spot on. The PHS doc is well worth it. I "do" have the doc myself. I would think most people on this forum have it also if they've had their car for awhile. Some people purchase the doc even b/4 they buy a certain car to verify the car is everything the seller says it is. Especially if the seller is claiming it to be all original equipment. I do not have the window sticker as of yet. I have seen them and would be cool to have. 

I would definitely talk to the guy who's 40 miles away. He may have all kinds of info about the car. You never know, you may get lucky on the block. If nothing else, maybe he could direct you to where it went. Good luck......


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## geeteeohguy (Feb 2, 2008)

The 7k3 heads are good heads to run these days on a pump gas motor. You can mill them a little bit, to get around a 90cc chamber, and you'll be running about 9:1 compression with the big valves. I'd keep those heads, if it were mine! Good find, and good luck with it. You're well on your way!


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## Lukeduk1980 (Jun 22, 2009)

Well, looks like a have a direction to go in. Thanks again for the help again guys. I will be contacting PHS on that history. Do you guys know if they can do it for Cameros? My neighbor has a 1972 SS Camero and would absolutly love to get those records. Can they do it for Chevrolet??

Lucas:shutme


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## Lukeduk1980 (Jun 22, 2009)

What is the difference between the engine block from 1973 compared to a standard 1968 gto 400 cid engine block? I know the horsepower ratings are different but was the cam or crank different? Are these 71-72 head, are they better then the 1968 heads? Any input would be greatly appreciated. Thanks again guys.

Lucas:shutme


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## 68greengoat (Sep 15, 2005)

As far as the heads go, you're running a 96cc head where for the most part in '68 they were 72 -75cc. Which equated to higher compression/hp. Is a '72 head better? Not if your looking for more hp. A #16 '68 head would get you up around 350/360hp.


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## Lukeduk1980 (Jun 22, 2009)

Well, I got some interesting results, I talked the the 2nd previous own of the car (exwife) and found that the car may have been built profesionally. They stated that whenever they punched it, the car would "wave" back and forth and needed wider tires. Typically not something you would see on 190-250 HP motor. Still digging for information.

Lucas


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