What is the difference between C5TZ-17260-N and C5TZ-17260-H? Are they both for a 65 F250?

 

Yes, but there are different applications.

C5TZ17260N .. Speedometer Cable-64.80" long

Application: 1965/66 F100/250 2WD = 3 M/T (not w/O/D) / New Process 435 4 speed M/T / Warner T18 4 speed M/T.
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C5TZ17260H .. Speedometer Cable-90.60" long.

Application: 1965/66 F100/250 4WD.
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But wait, there's more!

C5TZ17260BS .. Speedometer Cable-93.60" long.

Application: 1965/66 F100/250 with MX Cruise-O-Matic (14 trans pan bolt holes).
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C5TZ17260Y .. Speedometer Cable-70.80" long.

Application: 1965/66 F100/250 with C-4 Cruise-O-Matic (11 trans pan bolt holes).
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All these cables are obsolete. I didn't bother searching for the 4WD cable.

Found the others at several Ford dealers, obsolete parts vendors.
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What's wrong with your original cable? Is the housing still in one piece?

Inside the housing is a steel core. The core needs lubercation, when they dry out, they bind in the housing and snap.

Autoparts stores sell a replacement core kit. Cut it to length, coat it with graphite, install it in the housing.
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Is the cable even defective? On the end of the cable is the speedometer driven gear.

The teeth could be stripped, causing the speedometer needle to jump around.

There's more than one tooth count (16 thru 21), There's more than one type of driven gear.

Some are plastic (all are still available from Ford), some have fiber teeth, some have steel teeth.

 

Bill,

Looks like the C5TZ-17260-Y would be the one for me. I currently have the speedo cable coming from the dash to a governor device mounted to the frame. From there another speedo cable runs into the trans. This device also has a vacuum line coming out of it. I want to bypass this entirely and run a cable from dash to trans. I checked Green Sales, no inventory for this one.
PS-Thanks a ton for the tip on the carb. Didn't get it yet, but I will let you know when it arrives.

 

You shouldn't have too much trouble getting a C5TZ17260Y speedo cable.

I found two sources that stock it.

Collectors Auto Supply in Oroville WA has 1 = 800-414-4462

Dennis Carpenter in Concord NC has 939 (that's right, 939!) = 704-786-8139