5-Bolt HiPo K-code 289 engine

  • Thanks for posting pictures. Just to clarify, I believe it's image 10 where you're referring to a Brinnel test? The rear counterweight had a section that was polished and inspected under a microscope to count nodules in specific area. I got that from a discussion with Bob Mannell about 20 years ago. There a few posts from Bob on this site about it too, here is one: 289 REAR MAIN CAP CASTING NUMBERS

    "My sources tell me that 289 HiPo cranks were 100% inspected, meaning each one had to be polished on the rear counterweight for inspection under a microscope. I was told that the inspectors were given pictures of what the grain pattern density should look like under the microscope. If what they saw looked close to the picture, it was good. If it looked like another picture, it did not pass."

    A Brinnel hardness test makes a depression in the casting with a ball bearing and there is usually no evidence of that on the crank. (If you look closely at a spindle, you will see a Brinnel mark on the back)

    Anyhow, for posterity and future reference, it would be helpful if you could add a few more images of the polished counter weight on your crank.

  • I currently have a few more pictures of the crank, including markings that may or may not be the stamp you are referring to. There is a stamp on the web forward of the #4 main cap that I can't make out but I have seen triangle stampings referenced online etc.. There is a small amount of orange paint left (pic 5) on that web as well. The polished counterweight you are referring to I believe is a from a grain count they do under a microscope to ensure quality. Not sure any other angles would help of that area.

  • I'm just curious... I have the sister to this one and she was cast on 4C24! What is the sequence number on your engine? Mine is number 5001.

  • Not sure what you mean by sequence number. You referring to the vin?

    All 1963-1964 five bolt bell housing High Performance 289 engines have a Ford Cleveland Ohio engine plant serial number hand die stamped into the left rear tooling boss of the cylinder block near the block deck surface for engines made before before July 12, 1964. Ford also hand painted HP and the serial number on the back of blocks during engine assembly. This serial number has nothing to do with vehicle identification numbers (VIN). Engines were used in Cobras, Fairlanes, Mustangs, early GT40s, Genie sports racers, Lotus 30s, and other new street and race cars is several countries on two continents. Ford and Shelby American sold crate engines with Shelby American offering professional endurance and drag race crate engines also.

    The most important number for restorers is the engine number. The next most important number for understanding how any engine was completed Day 1 is the engine assembly date on a pad in front of the left cylinder head.

    This illustration is one page of a slide show created to help original Cobra owners understand the important "numbers" on cylinder blocks in their original engines. August 25-26, 1964 engines were not numbered in the Cleveland Ohio plant so Shelby American created their own new number sequence. In the case below a Shelby American stamped engine number is where the Cleveland plant stamped their serial number previously.


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    Dan

    Edited 4 times, last by Dan Case (June 1, 2026 at 6:35 PM).

  • Mine has 5001 hand die stamped into the left rear tooling boss of the cylinder block near the block deck surface, as Dan described in his post and as he has shown in the bottom-right picture... what is your number? I noticed that my block was cast the same day as one of your heads!

  • Mine has 5001 hand die stamped into the left rear tooling boss of the cylinder block near the block deck surface, as Dan described in his post and as he has shown in the bottom-right picture... what is your number? I noticed that my block was cast the same day as one of your heads!

    Oh... serial number above clutch Z bar pivot, 6434...

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