Ummm, yeah could be, I must say my 78 used to stop dead half way to W'pk (work)(yes I drove it to work - it was bought to enjoy).
I'd be on Cowpasture Rd, ripping out the HEI, and dropping the old original (kettering) dissy back in.
But it would cough splutter, give enough warming to pull off the road. After that, no firing, no nuttin.
That night put HEI back in - everything worked fine, go to work next day, same all over again.
I changed every thing, I could possibly change in the HEI dissy - cap, coil, leads, module, wiring - never fixed it.
It now sits c/w leads on my coffee table as a reminder that there are things I cant fix.
Im pretty sure it was heat/time related - as it would stop to within a few feet of the same place on Cowpasture Rd every time..
So keep us informed, any info is most welcomen.