66 K-Code GT Fastback Production Numbers

This post is in response to a question posed by GT-Craig back in late 2021, asking if anyone knew how many 1966 K-Code GT Fastbacks were produced. There were no replies. Since then, as the owner of a 1965 (not '66) K-Code GT Fastback myself, I have given the question much thought and research. While there can be no definitive answer (production records being long gone), I think I can offer a reasonably informed "guestimate".

Specifically to GT-Craig's question, I believe that probably between 700 and 1000 K-Code GT Fastbacks were produced in 1966. Taking both 1965 & 1966 production years together, I would estimate that anywhere from 2000 to 3000 total K-Code GT Fastbacks were produced, with more made in 1965 (1300 to 2000) than 1966 (700 to 1000).

Unless anyone really wants to know, I will spare you all my calculations--- though the math is easy, the assumptions the calculations are based on are complicated and subject to interpretation and dispute. Nevertheless, I am comfortable with my conclusions.

Let me know if anyone wants more info. But be careful what you wish for!

I don't want to make your eyes glaze over with calculations, so I'll try to keep this (relatively) simple, while still citing sources for some of my assumptions.

The typical number for '65-'66 K-Code Mustangs is 12,742 (Tony Gregory, Peter Sessler and others). However, the 2+2 (fastback) wasn't introduced until about three months after the K engine was already available, so (assuming) about 500 K's per month, that means no more than (12,742-1500) = 11,242 K's were produced during the 2+2 production run.

The registry section of Tony Gregory's excellent book on the K-Code Mustang (4th ed.) indicates (out of about 1,400 K's registered), that about 50% are 2+2's. This is a much higher percent than coupes or convertibles. My guess is that many buyers were seeking to obtain a "budget" Shelby GT-350.

Anyway, if about half (50%) of all K-Codes were 2+2's, and 11,242 K's were built coincident with the 2+2, then (0.5 X 11,242) = about 5,621 K-Code 2+2's would have been built in '65-'66. HOWEVER, this number includes both GT's and non-GT's.

The accepted number for TOTAL GT's built in '65-'66 is 40,596 (Sessler, et al.) Remember, all GT's HAD to have either A or K-Code engines. So, what was the proportion between the two? Nobody knows exactly, but obviously the less-expensive A engine would outnumber the K.

Using on-line figures from internet sources (Early Mustang & In Search of Mustangs), each of which has a registry of about 35,000 - 40,000 entries, I isolated the registered A and K Code cars. In both databases, the ratio of A-Codes to K-Codes is about 6.5 to 1, or put another way, K-Codes make up about 15% (15.3%) of all A and K-Code cars.

PRESUMING that the ratio of ALL K-to-A codes is the same (whether GT or non-GT) and 40,596 GT's were built, then about (15.3% X 40,596) GT's were K-Code cars, or 6,211 cars.

Further, if (from Gregory's database) about 50% of K-Codes were 2+2's, and 6,211 GT's were K-Codes, then half (50% X 6,211) GT's were ALSO 2+2's, or 3,105.

And, if 5,621 was the total number of K-Code 2+2's (from para. 4, above), and 3,105 of these were K-Code 2+2 GT's, then (5,621 minus 3,105) or 2,516 would the the total of NON-GT 2+2's made in '65-'66.

But you asked about 1966 non-GT 2+2 K-Codes specifically. My guess is that since (slightly) more K's were made in 1965 than 1966, the split would be about 1,300/1,200, or about 1,200 non-GT K-Code 2+2's made in 1966.

Obviously I have made a number of assumptions herein. It is possible that the proportion of K-Codes registered in on-line and published databases may exceed the actual number built, as owners of special cars (like the K) may be more inclined to register them. So the actual numbers may be smaller. Still, given the lack of any other numbers about K-Code GT and 2+2 production, my calculations are (I hope) better than nothing.

My rough guess is that maybe about 1,000 to 1,100 K-Code GT coupes might have been built in 1966, and a similar number in 1965. As you point out, all the '65's would have been 4-speed cars. For '66, (relying again on Tony Gregory's database), only about 11% of the K's would have an automatic, meaning there might have been only 110-120 K-Code GT coupes with an auto trans like yours. Pretty rare indeed! Remember too, like I said, the actual number could be smaller, as owners of special cars like these are probably more inclined to register them in the on-line databases, inflating the numbers relative to more common varieties of Mustang.

Consider this as well: I have read that the average survival rate for old cars is only about 25% or less, and not much higher even for special vehicles. I do know that the known survival rate for special cars such as the Chrysler 300 Letter cars (made from the mid-'50's to the early '60's) is less than 33%. Time takes its toll!

Right you are!!!

Okay--- those are two separate questions: Where did I get the 40,596 number for '65-'66 GT's, and where did I get the 12,742 number for '65-'66 K-Codes? If you re-read my posts you will note that I did cite sources in passing, but as you don't appear to be familiar with these, I will give you "chapter and verse", so to speak.

The number of '65-'66 GT's (40,596) comes from Peter Sessler's "Illustrated High-Performance Mustang Guide" (Motorbooks International, 1983). Sessler further breaks it down to 15,079 GT's in 1965, and 25,517 GT's in 1966. Another source, Jim Smart's "1965-1990 Mustang GT/Mach 1 Guide (TAB Books, 1989) has the same number of GT's for 1966 (25,517), but differs slightly for 1965 (15,106), making the total slightly higher than Sessler (40,623 vs. 40,596). Apparently between the publication dates of 1983 to 1989, Jim Smart found another 27 GT Mustangs! Jim Smart, it should be noted, may be best known for authoring (with Jim Haskell) the two-volume "Mustang Production Guide".

As for the 12,742 K-Code Mustangs built in 1965-1966, Peter Sessler gives this number in his book; also Tony Gregory gives the same number in his book, "The 289 High Performance Mustang" (4th Ed., Performance Publications 2006).

Are these numbers accurate? All these authors know far more about early Mustang production than I do, and I trust they did their homework.

Hope that answers your questions!

"How many actually exist now?" As I said in a previous post, while it is impossible to know for sure, the typical survival rate for old cars is only 25-33%, usually less.

As for shops in Virginia, being in California I couldn't say. HOWEVER, the first place I would check is Virginia Classic Mustang (http://www.virginiaclassicmustang.com). While they are in Virginia, they are not exactly close to you, and they probably don't work on cars anyway. BUT, they are good people and may have a good recommendation or two as to where you might take your Mustang. Good luck!

"I would like to know where Pete got his numbers for GTs."

Well, you asked me where i got my numbers, and I told you, citing numerous sources. Now you want to know where they got their numbers. I guess you'll have to ask THEM.

I too have read that production records for the '65-'66 Mustangs were destroyed, and detailed chassis information, such as Marti has for the '67-up Mustangs, is unavailable.

However, that doesn't necessarily mean ALL '65-'66 production numbers are gone. For example, it is widely acknowledged that 607,568 Mustangs were built in 1966. So obviously, some data exists.

Since you remain unsatisfied, I'll leave it to you to make appropriate inquiries of Messrs. Sessler, Smart, Gregory, etc. Do share with us what you learn, as I'm sure we'll all be curious to hear what you find out!

Regarding your calculations about K-code Mustangs, Tony Gregory specifically states in his book that his enumerated total of K-code Mustangs does NOT include Shelbys. At least he says so specifically for the 7,273 K-code Mustangs made in 1965; and, I believe he is implying likewise for the 5,469 made in 1966. If so, your calculations are in error by deducting Shelbys from the totals.

Now I grant you, it seems logical to include Shelbys in the 12,742 K-code Mustangs produced in '65-'66. After all, if I were a junior Ford beancounter in San Jose back then tasked with tallying how many K-code Mustangs went out the door, it wouldn't matter to me whether they went to Shelby or any other dealer. They were still Ford K-code Mustangs until AFTER Shelby got through with them.

But Gregory seems to think otherwise. I'm not sure why, but (don't hold me to this!) it may have to do with the K-code numbers for 1967, where, because the Marti records exist for the 472 K's built, it is known this does NOT include the Shelby K's. So the same distinction is carried back to '65 & '66 (i.e., Shelby and non-Shelby K's are counted separately). Thought I read that someplace, but can't remember where!

As for the ratio of A-code GT's to K-code GT's, computing from data in Jim Smart's "in Search of Mustangs" website, for ALL A's & K's registered there (not just GT's) the numbers work out to 85% A and 15% K. I might expect the ratio (85/15) to be similar for GT's, but lacking more information, I guess it's impossible to know.