Author Topic: Decode 66 GT Engine Numbers  (Read 242 times)

Offline Tiny

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Decode 66 GT Engine Numbers
« on: January 12, 2018, 02:47:11 AM »
Hi all, I have a 66 GT Coupe.  Built in Late October 65 'K' I was wondering if my engine would be original to the vehicle.  What I can discover is that the engine casting (C5AE-6015E) tells me the engine was originally designed for a Galaxie, is this the case?  The engine number (4K6F) tells me it was built in 1964.  Does all this seem correct for my 66 GT or is it the case that its not likely to be the original engine.

Cheers
66 San Jose Built A Code GT Coupe
289 4V, C4, PS, No A/C

Offline Hipo giddyup

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Re: Decode 66 GT Engine Numbers
« Reply #1 on: January 12, 2018, 09:50:44 AM »
 This block seems to be a year older than what you should have. I believe you should have a 5J or 5K assemlby if your car was an October 65' build.  Let's see what others have to say.
1967 Springtime Yellow Coupe, 289 2v 3spd, Metuchen built, Nov. 17th 66'
1966 Sahara Beige Coupe, 289 2v 3spd, Dearborn built, July 21st 66'
1964 1/2 Pagoda Green Coupe, 260 2v 3spd, Dearborn built, June 30th 64'
1966 GT350 Fastback clone, 289 HiPo, 725cfm Holley, 4spd, SanJose built, Nov 25th 65'

Offline sglbbs

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Re: Decode 66 GT Engine Numbers
« Reply #2 on: January 12, 2018, 11:05:29 AM »
This block seems to be a year older than what you should have. I believe you should have a 5J or 5K assemlby if your car was an October 65' build.  Let's see what others have to say.
+ 1 or maybe a 5H.

What dates are on the heads, intake, exhaust etc?
66 GT 6T09K12---- scheduled Oct 14, bucked Oct 13 '65

Offline jwc66k

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Re: Decode 66 GT Engine Numbers
« Reply #3 on: January 12, 2018, 11:24:37 AM »
What I can discover is that the engine casting (C5AE-6015E) tells me the engine was originally designed for a Galaxie, is this the case? 
Yes. Look at the part numbers on your distributor. The correct, 66 non-smog distributor would have a part number of C5GF-12127-A which is a distributor originally designed for a Comet.
Built in Late October 65 'K' I was wondering if my engine would be original to the vehicle. 
The casting and engine assembly dates indicate a 1964 build which would not be the correct engine for your Oct 65 build car.
Get into the habit of entering the first eight characters of your VIN when posting questions (example - 6R07A120xxx is my hardtop).
Jim
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Offline suskeenwiske

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Re: Decode 66 GT Engine Numbers
« Reply #4 on: January 12, 2018, 04:01:48 PM »
My Engine Casting Date is 4M1, which I thought indicated December 1, 1964. In this case how does 4JB1 break down? Also, wouldn't 5G be a possibility for the correct Block for his car?

Ray
Ray
1965 Dearborn Coupe
6 Cylinder, AT, PB, PS, AC
Est. Build 23A

Offline jwc66k

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Re: Decode 66 GT Engine Numbers
« Reply #5 on: January 12, 2018, 07:21:00 PM »
My Engine Casting Date is 4M1, which I thought indicated December 1, 1964.
Yes.
In this case how does 4JB1 break down?
Ray,
Where did you find 4JB1? If anything, I would look for a number in the third position on an engine assembly date stamp, as in 4J8. The last letter has been an assembler/inspection code, usually a letter. You need to do some cleaning to make a determination if it was lightly stamped. If so, any letter with a straight vertical line on the left "could" be used, except "I" (like B, D, E, F, H, K, L, M, N, P, and R) as an assembler/inspection code. Also, the number after the month letter could be one or two characters.
Jim
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Offline Tiny

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Re: Decode 66 GT Engine Numbers
« Reply #6 on: January 12, 2018, 07:26:06 PM »
Interesting comments, thanks everyone. My Vin is 6R07A121...... .  With the engine being an Oct 64 build with the vehicle being an Oct 65 build is a long time for the engine to sit around before it was put in the car so it does seem like it is not the correct engine.  Also the last digit of the engine number "F" what does it mean? I get the first 3 digits, 4K6 which I believe to be 1964 Oct 6th.
66 San Jose Built A Code GT Coupe
289 4V, C4, PS, No A/C

Offline jwc66k

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Re: Decode 66 GT Engine Numbers
« Reply #7 on: January 12, 2018, 08:55:10 PM »
Interesting comments, thanks everyone. My Vin is 6R07A121...... .  With the engine being an Oct 64 build with the vehicle being an Oct 65 build is a long time for the engine to sit around before it was put in the car so it does seem like it is not the correct engine.  Also the last digit of the engine number "F" what does it mean? I get the first 3 digits, 4K6 which I believe to be 1964 Oct 6th.
The Oct 64 dated engine is most likely NOT original. The "F" on the assembly date is the assembler/inspector code (we don't know which yet).
My Oct 18 "K" Fastback is 6R09K121xxx (a Monday), engine is 5H23. My Oct 15 Hardtop is 6R07A120xxx (a Friday), engine 5G21.
Jim 
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Offline suskeenwiske

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Re: Decode 66 GT Engine Numbers
« Reply #8 on: January 12, 2018, 08:57:28 PM »
Where did you find 4JB1? If anything, I would look for a number in the third position on an engine assembly date stamp, as in 4J8. The last letter has been an assembler/inspection code, usually a letter. You need to do some cleaning to make a determination if it was lightly stamped. If so, any letter with a straight vertical line on the left "could" be used, except "I" (like B, D, E, F, H, K, L, M, N, P, and R) as an assembler/inspection code. Also, the number after the month letter could be one or two characters.
Jim
[/quote]

Are we talking about the same thing? You mentioned Assembly Date Stamp, I'm referring to the Casting Date that is above the Engine Part Number in the first photograph. In terms of the 'B' or 8 ,the 3rd character, I thought might indicate the Assembly Plant such as Buffalo...if Engines were cast there. The last Character, to me, looks like a '1' rather than an I. As I understand it, Ford did not use the letter 'I' in order to avoid any confusion whether it's a 1 or not. Additionally, someone correct me because I'm not sure, I thought the last Character indicated the Shift that Cast the Block.

Ray
Ray
1965 Dearborn Coupe
6 Cylinder, AT, PB, PS, AC
Est. Build 23A

Offline jwc66k

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Re: Decode 66 GT Engine Numbers
« Reply #9 on: January 13, 2018, 12:23:00 AM »
Ray,
The block casting date is by the starter, the engine assembly date is stamped on the left front near the distributor.
Jim
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Offline J_Speegle

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Re: Decode 66 GT Engine Numbers
« Reply #10 on: January 13, 2018, 01:19:05 AM »
The Oct 64 dated engine is most likely NOT original. The "F" on the assembly date is the assembler/inspector code (we don't know which yet).

The "F" would be the assemblers initial according to Fords documents
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline jwc66k

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Re: Decode 66 GT Engine Numbers
« Reply #11 on: January 13, 2018, 12:25:35 PM »
The "F" would be the assemblers initial according to Fords documents
It seems that code was finally figured out.
Jim
I promise to be politically correct in all my posts to keep the BBBB from vociferating.

Offline suskeenwiske

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Re: Decode 66 GT Engine Numbers
« Reply #12 on: January 13, 2018, 03:34:52 PM »
Ray,
The block casting date is by the starter, the engine assembly date is stamped on the left front near the distributor.
Jim

I was not referring to the Assembly Date. You asked where I found 4JB1, the Casting Date. I was only asking how this Casting Date would be deciphered? The '4' and 'J' I understand but was wondering what the 'B1' portion of the Casting Date meant as my Block has a 3-Character Casting Date, (4M1), as opposed to a 4-Character Date? I did not find anything on-line or in my Manuals that explained with any consistency what the last two Characters actually meant.

Since the original question had to do with whether the Engine Block was correct for Tiny's car, which likely it's not and which, for it to be correct would likely need to start with 5G, H, J or K, I was inquiring about the meaning of the last two Characters in order to understand if there is any significance to these two Characters in order for the Block to be correct for Tiny's car.

Thanks

Ray
Ray
1965 Dearborn Coupe
6 Cylinder, AT, PB, PS, AC
Est. Build 23A

Offline J_Speegle

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Re: Decode 66 GT Engine Numbers
« Reply #13 on: January 13, 2018, 06:04:12 PM »
I was not referring to the Assembly Date. You asked where I found 4JB1, the Casting Date. I was only asking how this Casting Date would be deciphered? The '4' and 'J' I understand but was wondering what the 'B1' portion of the Casting Date meant as my Block has a 3-Character Casting Date, (4M1), as opposed to a 4-Character Date? I did not find anything on-line or in my Manuals that explained with any consistency what the last two Characters actually meant.

I think you'll find this was not a clean casting date and your "B"  was suppose to be a "3" which would make the date Sept 31, 1964 fitting in with the typical use and application we've seen on these blocks The other (less likely IMHO ) possibility it that the worker inserted the wrong digit in the holder in that place
Jeff Speegle

Anything worth doing is worth doing concours ;)