I have Never known the Asphalt Cloth to be "Split", it is woven and does not hold shape when spilt axially. They do make a modern corrugated plastic tubing that is split.
Ebay, American Auto Wire and Local Swap meets are good sources for this item, I have had trouble sourcing locally & often get a blank stare at my Counter man when searching for the Gooey Cloth.
I this used in basically two places on the F Body: Temp Sender and the Start leads.
A friendly suggestion for hiding the pertronix lead would be to procure some Harness (NON ADHESIVE) Tapes and re-wrap or over wrap as needed.