Joe,
I went back to a catalog that was 30 years old and it called for the 193077 V belt, listed as a 15 1/2" belt. The new catalog list the 193077 as a 15 3/8 belt. I guess these belts have shrunk in the past 30 years. Seems like it should fit better.
I also took the belt off my 328 and it is labeled 193077.
Cathy