[Curnane]

Hi Guys found out today that my car does not have the origanal rear end the one that is in it has the cast number 9783389 then k 1 3 6 looks like a 66 rear we did some research through some old books and it looks like an olds rear
not sure we belive it has 433 gears its 10 bolt and has 4 spider gears . Can anyone help me decode this I would like to locate the correct rear if possible if not this one will have to do for now I do have the phs docs not sure what to look for

[Dick Boneske]

Where did you find the casting number? My '64 also has had the rear end replaced before I bought it. It's now a 3.23 ration open--no Safe-T-Track.

The '64's are the only ones with smaller bushings on the top of the housing where the control arms are attached. Other years have all eight bushings the same size.

If you weren't so far away, I would definitely be interested in buying the one you now have. I believe shipping to Wisconsin would be really expensive. They must weigh about 275 lb.

[Curnane]

Originally Posted by Dick Boneske

Where did you find the casting number? My '64 also has had the rear end replaced before I bought it. It's now a 3.23 ration open--no Safe-T-Track.

The '64's are the only ones with smaller bushings on the top of the housing where the control arms are attached. Other years have all eight bushings the same size.

If you weren't so far away, I would definitely be interested in buying the one you now have. I believe shipping to Wisconsin would be reahelly expensive. They must weigh about 275 lb.

I found it on the passenger side close to the pumpkin I did some research on a recent post on this forum about rear ends and its starting to look like this may be the origanal rear end housing. My car came with a k code rear 3.23
looks like it was redone to 4.33s some one had this car beefed up. According to this recent post that is exactly where the code is

[Dick Boneske]

Your original post noted a casting date ending in 6. This would not be a '64 rear end. Also, does it have the small or large bushings on top of the housing near the pumpkin? All '64's used smaller ones in this location only.

[Curnane]

Originally Posted by Dick Boneske

Your original post noted a casting date ending in 6. This would not be a '64 rear end. Also, does it have the small or large bushings on top of the housing near the pumpkin? All '64's used smaller ones in this location only.

There is a casting number then k 136 not sure if that represents a date there is suppose to be a k there I will let you know about the bushings I need someone to look up the casting number on the housing here it is 9783389. I have been to numerous web sites and found no information

[Dick Boneske]

Thanks for the info on location. I didn't know the casting number was on the bottom side of the pumpkin casting. your letters K 13 6 represent November 13, 1966, which would make this likely a '67 rear end. Your casting number 9783389 makes it a Pontiac part, not Olds.

My '64 GTO rear end has a casting code K 21 4, which is November 21, 1964, making it a '65 rear end. Casting number is 9779822, also a Pontiac part number.

I thought there was a stamp on one of the axle tubes showing a code for the original gear ratio. This I can't find. Counting wheel turns vs. drive shaft turns tells me mine is a 3.23.

[Old Man Taylor]

I think the factory Pontiac stamping was on the back of the passenger side axle tube close to the center section.

[Curnane]

Originally Posted by Dick Boneske

Thanks for the info on location. I didn't know the casting number was on the bottom side of the pumpkin casting. your letters K 13 6 represent November 13, 1966, which would make this likely a '67 rear end. Your casting number 9783389 makes it a Pontiac part, not Olds.

My '64 GTO rear end has a casting code K 21 4, which is November 21, 1964, making it a '65 rear end. Casting number is 9779822, also a Pontiac part number.

I thought there was a stamp on one of the axle tubes showing a code for the original gear ratio. This I can't find. Counting wheel turns vs. drive shaft turns tells me mine is a 3.23.

Thanks Dick do you know if its ok to use this rear end is it the correct width?
I would like to find a correct dated rear end for my car I ll bet thats going to be close to impossible my car was built april 15th 64 what would be an acceptable date?

[Dick Boneske]

'64/'65 rear ends measure exactly 53" from the inner edge of the brake drum to the same place on the opposite side. I checked my wife's '64 with the original rearend and my chassis with the '65 rearend.

For your '64, a date somewhere in March of '64 would be acceptable. You must one of the first '64 GTO's built.

[Curnane]

Originally Posted by Dick Boneske

'64/'65 rear ends measure exactly 53" from the inner edge of the brake drum to the same place on the opposite side. I checked my wife's '64 with the original rearend and my chassis with the '65 rearend.

For your '64, a date somewhere in March of '64 would be acceptable. You must one of the first '64 GTO's built.

Dick not sure how to tell what number my car is ? Is it in the vin number?
In your recent post you mentioned your rear end had a date of k 1964 and it was probly a 65 rear end why would that be ? I am also doing some
research on my tranny someone told me that the vins were not stamped on all of them but the correct case was a 325 case for both m20 and m21 ?

[Dick Boneske]

Your VIN number shows a model number (824), where built, and a serial number. You said your car was built in April, so all the casting dates would be previous to that. The '64 GTO was introduced midway through the model year. The first '64 GTO's were sold in early 1964, not September of '63 like the other 1964 Pontiacs.

The reason I say the rear end in my car is a '65 is that at the casting date of Nov. '64, Pontiac was already building '65 GTO's. In those years, new model year cars were introduced in September of the previous year, so casting dates for '65's could be earlier than even 9 XX 4.

If you are going to try to keep your car all-numbers-matching, it's understandable that you're worried about the transmission VIN and date codes. However, are you aware that the brake drums, steering box, windshield wiper motor assy., and many other items also have date codes on them? You may want to consider keeping the original parts you already have on your car, but replacing or adding what you want, irrespective of date codes. Just my two-cents worth.

[Curnane]

Originally Posted by Dick Boneske

Your VIN number shows a model number (824), where built, and a serial number. You said your car was built in April, so all the casting dates would be previous to that. The '64 GTO was introduced midway through the model year. The first '64 GTO's were sold in early 1964, not September of '63 like the other 1964 Pontiacs.

The reason I say the rear end in my car is a '65 is that at the casting date of Nov. '64, Pontiac was already building '65 GTO's. In those years, new model year cars were introduced in September of the previous year, so casting dates for '65's could be earlier than even 9 XX 4.

If you are going to try to keep your car all-numbers-matching, it's understandable that you're worried about the transmission VIN and date codes. However, are you aware that the brake drums, steering box, windshield wiper motor assy., and many other items also have date codes on them? You may want to consider keeping the original parts you already have on your car, but replacing or adding what you want, irrespective of date codes. Just my two-cents worth.

Thanks Dick I thouht they came out in 63. I still have 2 questions the first is have you heard of some trannys coming through without vins and are they the 325 case ?
The second is how do I tell the prodution number ?

[Dick Boneske]

Curnane,
I don't know if '64 GTO's had VIN number on the cases. I can't find one on my original '64 Muncie 4 speed. I bought a '64 GTO new in 1964 and still have the original transmission. The car was lost in a house fire, but I saved the drivetrain.

Your question about production number, I assume refers to how many cars were built before yours. The closest thing to this is the VIN number and your PHS documents which tell you when your car was built. This production date is also stamped on the frame about half way between the rear wheel and the rear bumper on the driver's side. It is on the outside vertical edge of the frame rail and appears in numbers about 3/8" high. Mine says 5-25-64. The VIN is also stamped on the frame rail on the driver's side but on top, so it can't be seen without a mirror. These numbers are only about 3/16" high, so they won't be easy to find. The numbers are located about 6" behind the center frame bulkhead that supports the gas and brake lines and again about 35" behind that same bulkhead.

I did read that the Silver '64 GTO that Pontiac restored at the factory about 10 years ago is the first one built.

[Old Man Taylor]

The first '64 GTO's were sold in 1963. The first time I saw one was in the parking lot at the drag strip. I did not know what it was but I liked it. Then the magazine article came out about the GTO's and I went down and test drove one. I ordered one the end of January just as I finished college. It was months before that when I took the test drive. I know they were available in November, and they might have been available in October.

[Old Man Taylor]

The first 1964 GTO production question stuck in my mind after this post. I have not yet found the first delivery date, but I did find references to the car being available in October. I also found this quote "Frank Bridge's sales forecast proved inaccurate: the GTO package had sold 10,000 units before the beginning of the 1964 calendar year, and total sales were 32,450."

Next time I see Jim Wangers I will try to remember to ask him the first availability date.

[John V.]

The 1st production '64 GTO's were the virtually identically prepared Zone Announcement Silvermist Gray Convertibles, one produced for each Zone. Final assembled in SEPTEMBER, 1963. They were made available to newspaper and magazine writers by the local zone to generate IMMEDIATE interest in the new GTO option package for the Lemans. Not long ago the GTOAA published the PHS copied Manifest record for one of these cars along with a reprint of an article featuring one of these cars which appeared in The Dallas Morning News by their auto editor at the time. The article appeared in the OCTOBER 14, 1963 issue of that daily, an article headlined "Pontiac's GTO Has 'Tiger Personality'".

The GTOAA article includes its own share of misinformation which I pointed out to them. My own '64 GTO was assembled NOVEMBER 20, 1963 at the Fremont Plant and I have documented at least one earlier example from that Plant and have no doubt many more were produced there and at the Pontiac Plant prior to mine. Haven't yet documented such early examples from the Baltimore or Kansas City Plants but suspect they are out there.

The GTO option was available from the start of '64 model year production. Pontiac Final Assembly Production began in September '63 for the '64 model year and cars began shipping to the dealerships at that time. The official "opening day" was October 2 IIRC and it would have been a violation of GM dealer rules to sell a '64 prior to that date to give all dealers a chance to build some stock inventory. The Lemans Hardtop was announced just after "opening day" and proved to be a big hit. I do not know when the first production Lemans Hardtop was assembled, but pretty sure no later than mid October. No idea when the first Hardtop with GTO option, but the Hardtop and the GTO option were very popular from the start, so it could not have taken too long. PMD churned out on average over 100 GTO equipped Lemans' every production day.

The casting p/n of the cast center section cannot tell you the application of the rear end assembly. The casting p/n 9783389 is unfamiliar to me. It is a Pontiac Engineering issued p/n but unless you are reading it wrong (a distinct possibility), it may be a casting with some peculiar change that was produced for Olds or Buick perhaps. Otherwise, I would expect it to be casting p/n 9783393. This center section casting was used in the Pontiac A body rears during '66 & '67 and also was used as the center section for the '67 Firebird rears even though the Firebird rear did not need the bushing ears ('68 Firebird got a new casting without ears). If it is clearly 9783389, it is possible that Pontiac assigned a specific p/n for a casting that may have specified an alternate metallurgy for the cast iron. I'm aware that Pontiac Engineering issued such p/n's but I've not seen this with center section castings in a Pontiac before. Chronologically, the p/n was assigned at the same time as the familiar 9783393 center section casting, so the vintage of the application would be identical, most likely 1st used for the '66 model year.

The cast date code K136 simply tells you the date the center section was cast. Does not define what axle tubes were pressed into it, what ring & pinion gear combo or differential type was originally assembled in it, etc. For that, you would have to find the stamped 2 letter Rear Axle Manifest Code typically stamped on the back of the passenger side axle tube, usually 2"-6" outboard of the socket where the axle tube is pressed in and below the brake line. Even the cast date decode is not certain for late 1966 calendar year castings. The foundry used an "M" that year only. They always used "I" to represent September (old myth was that "I" was not used by the Foundry, totally false) and with 12 months, Dec. was "L". But somehow Mxx6 cast dates have turned up, so it is unclear if K136 would be November 13, 1966 or possibly October. Either way, little doubt (if you are not misreading the cast date), this center section casting was assembled into an Axle Tube & Differential Housing Assembly and then became part of a complete Rear Axle Assembly intended for use in a '67 automobile. The Rear Axle Manifest Code would decode the ratio and differential type (locking or open) that went into it originally, no telling what is in it now.

To my knowledge, the original '64 model year center casting section does not have the casting p/n cast on it (although the p/n is known). It does have the small ears on it which is the way to identify it. However, by May 31, 1964 (earliest cast date code I'm aware of), the foundry had already started casting the new center section casting p/n 9779822 and very late built '64 A bodies (which includes GTO optioned Lemans') with original rear axle assemblies will turn up with this center section casting. The 9779822 casting was used throughout the '65 model year.

To my knowledge, Pontiac increased the width of the rear axle assembly using longer axle tubes and axles for the '66 model year A body (some claim '67). No real problem using a '67 Pontiac A body rear axle assembly in a '64 (assuming that is what you have), the track is just a tad wider.

Generally speaking, the partial VIN (omits the prefix like 824) was stamped at the Final Plants on top of the rear flange of the trans main case for the Muncie 4 speed in '64. The main case p/n was 3851325, same used in '65 although the bolt lug at the top rear changed shape a bit for '65. There is a Muncie stamped code at the lower right corner near the side cover opening which decodes the date of trans assembly. There was also originally a p/n tag bolted to the side cover which would match the Pontiac specified p/n for the particular application. There were two choices, one for all applications except 3.90 rear gear (code W trans) which had an 8 tooth speedo drive gear in it and one for the 3.90 rear gear application (code 9 trans, this wasn't just for GTO application, other combos could get a 3.90 rear gear depending on engine and optional equipment, see the Axle Chart in the MPC for details) which had a 6 tooth speedo drive gear in it. The external speedo driven gears were installed at Final Assembly and depended on rear axle ratio and tire sizing but the speedo drive gear was specific according to trans p/n.

Both of these choices were wide ratio Muncies, designated as GM UPC M20 (and why we call it an M20 today). I have never found a single documented example of a close ratio Muncie made available for the '64 model year or any factory documentation announcing the availability. The famous Car & Driver article suggested a close ratio but the ratios listed were for a B-W trans, not a Muncie, so the claim is immediately suspect. Some '64 GTO Sales Brochures were printed indicating the availability of a close ratio 4 spd but it is unclear if that mention was from early copies and later removed or from later copies suggesting a late announcement. Still, no actual '64's have been documented to have been built with the M21 though plenty got 3.90 gears. In '65, the close ratio trans was an option offered on the All Series Special Equipment Order Form. It required Tri-power, 3.90 gears, and other odds and ends and was designated code 8. You could still get a GTO with 3.90 gears and a code 9 wide ratio M20 Muncie. In fact, since the M21 required Tri-power, all 4 bbl GTO's with 3.90 gears and 4 speed remained M20 equipped. If the M21 ever did make production in '64 (I remain skeptical), I'm fairly certain the same mandatory options as noted for '65 would have been put in place. Unfortunately, I have never found a copy of the 1964 All Series Special Equipment Order Form, only the 1965 version, so I can't say for sure that it was never listed in '64. The ASSE Order Form was not commonly used and many salesmen were probably fairly oblivious to what might have been on it in the way of performance options. As example, Trailer Package Options were ordered on it but even that wasn't very common. The Quick Ratio Manual Steering Box was ordered on the '64 ASSE Order Form and that WAS a pretty common GTO option, so I would suggest that if a close ratio trans was on that Order Form, at least a few buyers would have checked it off and the cars would have been built. Personally, I think that option was kept in reserve after being initially considered, to give Pontiac something new to offer for the '65 model year.

Shorter rear gears (higher numeric gears) for both years were available thru the MPC but were not available as factory equipment. If you wanted such a gearset, the sales literature suggested you had to factory order the 3.90 gears. I believe this was mainly so that the trans internal speedo drive gear would be the correct 6 tooth one, plus it would have meant the car would have already been equipped with the other mandatory options associated with the 3.90 rear, protecting the warranty concerns for these high numeric geared combos.

No way to determine how many GTO's were built before yours. As an April built car, suffice to say that at least 1/2 of all '64 GTO's were already built by then. The last '64 model year cars were assembled either in the last days of July '64 or the first few days of August, 1964. The Data Plate will tell you how many Lemans body assemblies of the same body style as yours (Hardtop, Coupe, or Convertible) were fabricated by Fisher Body at the Plant where yours was built. Example, if yours is a 37 body style Hardtop built at Fremont and has Body No. BF4321, you will know that the Fremont Fisher Body Plant had already put together 4,320 Lemans 2 dr. Hardtop bodies (more than a few of which would have been GTO optioned) by the time they put your body together. Cars were not necessarily sequenced to the Final Line in consecutive order by Body Assembly no. or VIN, and there were 4 different Final Assembly plants building Pontiac A bodies each with their own Body Nos. and VIN's, so trying to determine how many GTO's had already been assembled by the time yours spent the 70 minutes or so on the final line to be slapped together is an impossible task.

I have often wondered about the reported '64 GTO production Sales Figures. Pontiac would report Model Year Production but it was also common, perhaps more common, to report Calendar Year Production. Since I do not know the source for the 32,450 figure accepted by the hobby as the '64 GTO total, I have often wondered if this no. is correct or if it perhaps represents 1964 Calendar Year Production. If it did, it would omit 1963 production of '64 GTO's but include 1964 production of '65 GTO's. I do not believe PHS has combed thru all '64 Model Year records to establish a model year total, so I presume somebody has relied on a report of sales records. If that somebody was unaware that GM typically reports Calendar Year sales figures, he may have misinterpreted the nos. found. Not real important, just my way of suggesting if you have not researched it yourself, and the source is not corroborated, you should take it with a grain of salt.

By the way, I am not infallible. My own source material is pretty broad and supported by study of actual cars over the past almost 35 years, simply because the '64 GTO fascinates me. I did not own one new but I have been passionate about the '64 ever since becoming aware of them.

Sorry for the length of the post. I rarely check this site and almost never post. And I won't be making it a habit now. Hope some of it may be helpful to you.

['ol Pinion head]

Originally Posted by John V.

...........
By the way, I am not infallible. My own source material is pretty broad and supported by study of actual cars over the past almost 35 years, simply because the '64 GTO fascinates me. I did not own one new but I have been passionate about the '64 ever since becoming aware of them.

Sorry for the length of the post. I rarely check this site and almost never post. And I won't be making it a habit now...

Thanks for your War & Peace version of '64 GTO by the numbers.
Am sure CeePee is calling, g' bye now.

[Old Man Taylor]

John V - Great information, thanks. W/R/T the M-20 vs M-21 issue - I was discussing this with Jim Wangers about a year ago. He said they wanted to have them available in the GTO, but GM had not made enough of them and the ones they did make were committed to Chevrolet, most if not all for the Corvette.

[Old Man Taylor]

I asked Jim Wangers over the weekend when he thought the first GTO was actually bought by a "normal" customer. He confirmed John V's story above, and also said you could be sure the first ones were by the first or second week of October. I believe the hard top was first made in December, but I'm not certain.

[Curnane]

Originally Posted by John V.

The 1st production '64 GTO's were the virtually identically prepared Zone Announcement Silvermist Gray Convertibles, one produced for each Zone. Final assembled in SEPTEMBER, 1963. They were made available to newspaper and magazine writers by the local zone to generate IMMEDIATE interest in the new GTO option package for the Lemans. Not long ago the GTOAA published the PHS copied Manifest record for one of these cars along with a reprint of an article featuring one of these cars which appeared in The Dallas Morning News by their auto editor at the time. The article appeared in the OCTOBER 14, 1963 issue of that daily, an article headlined "Pontiac's GTO Has 'Tiger Personality'".

The GTOAA article includes its own share of misinformation which I pointed out to them. My own '64 GTO was assembled NOVEMBER 20, 1963 at the Fremont Plant and I have documented at least one earlier example from that Plant and have no doubt many more were produced there and at the Pontiac Plant prior to mine. Haven't yet documented such early examples from the Baltimore or Kansas City Plants but suspect they are out there.

The GTO option was available from the start of '64 model year production. Pontiac Final Assembly Production began in September '63 for the '64 model year and cars began shipping to the dealerships at that time. The official "opening day" was October 2 IIRC and it would have been a violation of GM dealer rules to sell a '64 prior to that date to give all dealers a chance to build some stock inventory. The Lemans Hardtop was announced just after "opening day" and proved to be a big hit. I do not know when the first production Lemans Hardtop was assembled, but pretty sure no later than mid October. No idea when the first Hardtop with GTO option, but the Hardtop and the GTO option were very popular from the start, so it could not have taken too long. PMD churned out on average over 100 GTO equipped Lemans' every production day.

The casting p/n of the cast center section cannot tell you the application of the rear end assembly. The casting p/n 9783389 is unfamiliar to me. It is a Pontiac Engineering issued p/n but unless you are reading it wrong (a distinct possibility), it may be a casting with some peculiar change that was produced for Olds or Buick perhaps. Otherwise, I would expect it to be casting p/n 9783393. This center section casting was used in the Pontiac A body rears during '66 & '67 and also was used as the center section for the '67 Firebird rears even though the Firebird rear did not need the bushing ears ('68 Firebird got a new casting without ears). If it is clearly 9783389, it is possible that Pontiac assigned a specific p/n for a casting that may have specified an alternate metallurgy for the cast iron. I'm aware that Pontiac Engineering issued such p/n's but I've not seen this with center section castings in a Pontiac before. Chronologically, the p/n was assigned at the same time as the familiar 9783393 center section casting, so the vintage of the application would be identical, most likely 1st used for the '66 model year.

The cast date code K136 simply tells you the date the center section was cast. Does not define what axle tubes were pressed into it, what ring & pinion gear combo or differential type was originally assembled in it, etc. For that, you would have to find the stamped 2 letter Rear Axle Manifest Code typically stamped on the back of the passenger side axle tube, usually 2"-6" outboard of the socket where the axle tube is pressed in and below the brake line. Even the cast date decode is not certain for late 1966 calendar year castings. The foundry used an "M" that year only. They always used "I" to represent September (old myth was that "I" was not used by the Foundry, totally false) and with 12 months, Dec. was "L". But somehow Mxx6 cast dates have turned up, so it is unclear if K136 would be November 13, 1966 or possibly October. Either way, little doubt (if you are not misreading the cast date), this center section casting was assembled into an Axle Tube & Differential Housing Assembly and then became part of a complete Rear Axle Assembly intended for use in a '67 automobile. The Rear Axle Manifest Code would decode the ratio and differential type (locking or open) that went into it originally, no telling what is in it now.

To my knowledge, the original '64 model year center casting section does not have the casting p/n cast on it (although the p/n is known). It does have the small ears on it which is the way to identify it. However, by May 31, 1964 (earliest cast date code I'm aware of), the foundry had already started casting the new center section casting p/n 9779822 and very late built '64 A bodies (which includes GTO optioned Lemans') with original rear axle assemblies will turn up with this center section casting. The 9779822 casting was used throughout the '65 model year.

To my knowledge, Pontiac increased the width of the rear axle assembly using longer axle tubes and axles for the '66 model year A body (some claim '67). No real problem using a '67 Pontiac A body rear axle assembly in a '64 (assuming that is what you have), the track is just a tad wider.

Generally speaking, the partial VIN (omits the prefix like 824) was stamped at the Final Plants on top of the rear flange of the trans main case for the Muncie 4 speed in '64. The main case p/n was 3851325, same used in '65 although the bolt lug at the top rear changed shape a bit for '65. There is a Muncie stamped code at the lower right corner near the side cover opening which decodes the date of trans assembly. There was also originally a p/n tag bolted to the side cover which would match the Pontiac specified p/n for the particular application. There were two choices, one for all applications except 3.90 rear gear (code W trans) which had an 8 tooth speedo drive gear in it and one for the 3.90 rear gear application (code 9 trans, this wasn't just for GTO application, other combos could get a 3.90 rear gear depending on engine and optional equipment, see the Axle Chart in the MPC for details) which had a 6 tooth speedo drive gear in it. The external speedo driven gears were installed at Final Assembly and depended on rear axle ratio and tire sizing but the speedo drive gear was specific according to trans p/n.

Both of these choices were wide ratio Muncies, designated as GM UPC M20 (and why we call it an M20 today). I have never found a single documented example of a close ratio Muncie made available for the '64 model year or any factory documentation announcing the availability. The famous Car & Driver article suggested a close ratio but the ratios listed were for a B-W trans, not a Muncie, so the claim is immediately suspect. Some '64 GTO Sales Brochures were printed indicating the availability of a close ratio 4 spd but it is unclear if that mention was from early copies and later removed or from later copies suggesting a late announcement. Still, no actual '64's have been documented to have been built with the M21 though plenty got 3.90 gears. In '65, the close ratio trans was an option offered on the All Series Special Equipment Order Form. It required Tri-power, 3.90 gears, and other odds and ends and was designated code 8. You could still get a GTO with 3.90 gears and a code 9 wide ratio M20 Muncie. In fact, since the M21 required Tri-power, all 4 bbl GTO's with 3.90 gears and 4 speed remained M20 equipped. If the M21 ever did make production in '64 (I remain skeptical), I'm fairly certain the same mandatory options as noted for '65 would have been put in place. Unfortunately, I have never found a copy of the 1964 All Series Special Equipment Order Form, only the 1965 version, so I can't say for sure that it was never listed in '64. The ASSE Order Form was not commonly used and many salesmen were probably fairly oblivious to what might have been on it in the way of performance options. As example, Trailer Package Options were ordered on it but even that wasn't very common. The Quick Ratio Manual Steering Box was ordered on the '64 ASSE Order Form and that WAS a pretty common GTO option, so I would suggest that if a close ratio trans was on that Order Form, at least a few buyers would have checked it off and the cars would have been built. Personally, I think that option was kept in reserve after being initially considered, to give Pontiac something new to offer for the '65 model year.

Shorter rear gears (higher numeric gears) for both years were available thru the MPC but were not available as factory equipment. If you wanted such a gearset, the sales literature suggested you had to factory order the 3.90 gears. I believe this was mainly so that the trans internal speedo drive gear would be the correct 6 tooth one, plus it would have meant the car would have already been equipped with the other mandatory options associated with the 3.90 rear, protecting the warranty concerns for these high numeric geared combos.

No way to determine how many GTO's were built before yours. As an April built car, suffice to say that at least 1/2 of all '64 GTO's were already built by then. The last '64 model year cars were assembled either in the last days of July '64 or the first few days of August, 1964. The Data Plate will tell you how many Lemans body assemblies of the same body style as yours (Hardtop, Coupe, or Convertible) were fabricated by Fisher Body at the Plant where yours was built. Example, if yours is a 37 body style Hardtop built at Fremont and has Body No. BF4321, you will know that the Fremont Fisher Body Plant had already put together 4,320 Lemans 2 dr. Hardtop bodies (more than a few of which would have been GTO optioned) by the time they put your body together. Cars were not necessarily sequenced to the Final Line in consecutive order by Body Assembly no. or VIN, and there were 4 different Final Assembly plants building Pontiac A bodies each with their own Body Nos. and VIN's, so trying to determine how many GTO's had already been assembled by the time yours spent the 70 minutes or so on the final line to be slapped together is an impossible task.

I have often wondered about the reported '64 GTO production Sales Figures. Pontiac would report Model Year Production but it was also common, perhaps more common, to report Calendar Year Production. Since I do not know the source for the 32,450 figure accepted by the hobby as the '64 GTO total, I have often wondered if this no. is correct or if it perhaps represents 1964 Calendar Year Production. If it did, it would omit 1963 production of '64 GTO's but include 1964 production of '65 GTO's. I do not believe PHS has combed thru all '64 Model Year records to establish a model year total, so I presume somebody has relied on a report of sales records. If that somebody was unaware that GM typically reports Calendar Year sales figures, he may have misinterpreted the nos. found. Not real important, just my way of suggesting if you have not researched it yourself, and the source is not corroborated, you should take it with a grain of salt.

By the way, I am not infallible. My own source material is pretty broad and supported by study of actual cars over the past almost 35 years, simply because the '64 GTO fascinates me. I did not own one new but I have been passionate about the '64 ever since becoming aware of them.

Sorry for the length of the post. I rarely check this site and almost never post. And I won't be making it a habit now. Hope some of it may be helpful
to you.

WOW BEST REPLY I HAVE EVER RECEIVED YOU SHOULD WRITE A BOOK IT WOULD MAKE IT EASIER FOR ALL OF US . NO JOKE! THANKS