Originally posted by Wrenchbender Ret.:
There have been 2 popular filters used on these. The dealer installed filters were AC. The aftermarket were Fram. The Fram cartridge number is C-4. I don,t remember the AC. (50 years ago) number. The Ac uses a 5/8 wrench on the cover bolt & the Fram uses a 7/8 or sometimes has a big wing nut. Any parts store should be able to come up with a cartridge or the specialty stores have them. The specialty stores usually go by diameter.
The diametrical difference between the Fram C21(P) and the C4 filters is as follows;
Outside diameter C4- 4 5/16 and C21P- 4.5 inches
Inside diameter C4 and C21P both 9/16
Height C4- 4 13/16 and C21P- 5 inchs
Gasket number(Fram) C4 151915 C21P 125405
Gasket dimetions
Outside diameter C4 4.75 and C21P 5.128
Inside diamter C4 4 11/32 and C21P 4 3/8
Thickness C4 1/16th and C21P 3/32nd
The Fram C21(P) interchanges with the AC115 and WIX 51100 and NAPA 1100 filters
The FRAM C4 interchanges with the WIX 51006 and NAPA 1006 filters
Hope this helps
Michael