Easy answer: They simply DID NOT indicate the running change for the hose on the Fast Ratio cars in the book. There are many examples where applications are omitted, or are vague, in virtually every year catalog that I have (55-74). These are the things you learn after 40 years of being associated with the same products.

Note insulator and solid pulley.

If you have the hose with the insulator on the AAR, then you should see 2891232 on the fitting. 3420194 did not use an insulator. Once again, 2891208 (stamped 2891208) is for the Saginaw pump.

Bill Rolik