4 speed speedometer cable failures?

[1967FEGT]

I have  a four speed big block car mustang. I had one cable fail from the right hand clip on the footboard coming out and melting the housing on the header.
I have had two of the Daniel Carpenter reproductions birdcage which breaks the driven gear when it fails.  There is nothing about lubricating the cable before installation. This time I ordered the AT4 cable lube and used a syringe to force thee tubes of lubricant in the housing and I reinstalled the cable twisting it as I put it back on the housing. Am I missing anything here that anyone can think of?

[RustyCrankshaft]

I've never actually broke the cable itself. I've had the drive end wear out, and I've had gears wear out, but I have yet to brake a cable. Well, I've broken a couple tach cables but they were on OLD equipment/marine engines.

The 73 camper special had a horrible needle bounce after I drug it out of the weeds and got it running. I did shoot a bunch of LPS in the cable when I had the gauges out for a couple weeks cleaning up the interior and that fixed it.

Are there any sharp bends in the cable that may be making it wear on the outter?

[machoneman]

Sure the gear didn't break first and then take out the cable?

[C8OZ]

It doesn't *sound* like the case here, but a surprisingly common cause of failure is a weak engine ground.

During starting, the difference is made up anywhere the current can find it, including the speedo cable and housing. Even if it doesn't kill them right away, the heat can shorten the life.