Early Mustang Engine Numbers

Q.

I have a classic car question that pertains to the engine size and year manufactured. I have a 1965 Ford Mustang and I can not find the location of the engine block serial number. Where is the serial number located and can you tell the block is a 260 64 1/2 by the serial number?

A.

The differences between 1964 ½ Mustangs and 1965 Mustangs is exactly the stuff perpetual arguments are made of. To the best of my knowledge, Ford did not use engine serial numbers in the mid sixties. The 5th digit in the cars VIN designates the engine size, and a “F” in this place would indicate the engine should be a 2-barrell 260-cubic inch V8. The year of the engine is designated by casting number; with the first letter “C” designating the sixties followed by a number. Which is right for a 1964 ½ “C4 or C5”, that is where one of many arguments begins. The date codes of the castings may give you a better idea, as the components need to be manufactured before the cars production.

From 1962 to 1964 1/2, Ford used the 260 V8 engine. This engine was the predecessor to the 289. The 289 was developed in 1963. The main difference between a 260 and a 289 is the 260 has a 6 inch space between the motor mount bolt holes, while the 289 has a 7 inch space.

All 260 engines have a 5-bolt bell housing bolt pattern. The 1963 and 1964 1/2 289 engines have the same 5-bolt pattern. The 260 has a smaller cylinder bore. Ford did not make a 260 4V engine. You can always add an early 289 4V intake to your 260 engine if you want to make a “D code” style engine (“D code” is a 1964 1/2 289 4V engine)

Wrench Safe,
Mark

Discussion
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9 Responses to “Early Mustang Engine Numbers”
  1. Ross

    From what I understand you are correct however adding a 4V to a 260 does not make it a “D” code. It’s an “F” code with an added 4V.

    Reply
  2. Thomas Cline

    The 5 bolt bell housing dilemma raises often. The source of many arguments… Thank you for your knowledge of this subject. Tom Cline

    Reply
  3. Charles Georgoudis

    The casting number is only that. A date that the engine block was cast and nothing more.It may give you an idea of the model year, but not necessarily. October was usually the date where new model years were introduced. A block that was cast in 1964 (C4) may have been installed into a 1965 model that was built in October through December of the previous year.
    The assembly date code is stamped into the block on a small extension at the left front side of the cylinder head deck surface, (left, while sitting in the car). This code can be erased if the head surface has been decked.
    Engines were usually assembled about three months in advance to installation, (when all goes well at the plant). The assembly date code gives the year, month and day of assembly followed by a letter for the assembly plant. This is not always stamped after the date code for some reason.
    An engine that has a code of 4L30C deciphers as: 4=1964, L=November, (L=consecutive number of the alphabet with the letter “I” omitted which results in the eleventh letter for the eleventh month), 30=day of the month, November 30, 1964. The letter “C” at the end, indicates the Cleveland assembly plant.
    This code was for a 289 that I have in my possession. An indication of the engine type and displacement is obviously not in this code. Ford didn’t stamp VINs on their small block engines in the 1960s, the only exception is on the “R” code 289, (289 HiPo), where the vehicle serial number is stamped into a pad located in the rear of the block.
    If there is a “W” at the end of the assembly date code versus a “C”, this would indicate the Windsor assembly plant where all 302 engines were built and some 289s. There has been instances where blocks that had a casting number designated for 302 engines were used for 289s in the final year for the 289 in 1968. A shortage of available 289 block castings facilitated the use of the 302 blocks. An example of this block is the casting number C80E-A, where both displacements can be found.

    Reply
  4. Tony Kovar

    Your earlier comments below from Charles Georgoudis are mostly correct with the exception of a few noteworthy things. First, HiPo “K” Code motors and their transmissions as well were all stamped with the VIN numbers of the cars that they were installed in from the Ford Factory. The only “K’ code motors without VIN number stampings were original ” K” Code Ford replacement Crate motors. Second, Starting in 1968, Most (but not all) Ford Plants started Stamping the VIN numbers of the cars on the engine blocks of the cars that they were installed in…but the practice was only done to about 50-60 percent of the cars during those years and after and the practice was not consistently spread throughout all of the Ford factories unfortunately. Tony K., MCA#70001

    Reply
    • Customer Service

      Hello Ken,

      Even some early ’65 motors had 5-bolt bell housings, by 1966 All 289’s and 302’s were 6-bolt bell housings.

      Thanks,

      Mark
      Classic Car Restoration Club Video Membership

      Reply
  5. Matthew Rose

    I have a ford head question. I have a set of heads on my 302. they are big valve big intake and exhaust ports . they have 1/2 head bolt holes. But they have no ford casting numbers at all. The one head has numbers cl 1991 and s/n sb 990-2 1181. The other head has numbers cl 2018 and s/n sb 990-2 1177 these are the only numbers on these heads. They also have screw in rocker studs . I’m trying to figure out what head I have can you help me ? Thanks

    Reply
    • Customer Service

      Hello Matthew,

      Ford Heads without casting numbers? I will have to refer your question to a couple of our Ford Experts and will let you know what I discover later this week.

      Thanks,

      Mark
      Classic Car Restoration Club Video Membership

      Reply
      • Customer Service

        Hello Mathew,

        After talking to a couple “Die-Hard” Ford guys they both have ideas but want to see pictures of the heads and valve covers also is you have pictures of the numbers on them that will help too.

        Thanks,

        Mark
        Classic Car Restoration Club Video Membership

        Reply