I have a '68 Standard with a 289 (2V) and the factory '68 air cleaner. I’m having a very difficult time finding the correctly sized air filter. O’Reilly’s and Auto Zone try to sell me the '67 style, which it too tall and has a diameter that is too small besides. Most online parts websites don’t give full dimensions. WCCC’s site does, and they truthfully admit it will not allow the lid to seal. 'Went to NAPA yesterday and bought a number 2116 which is very close which has a diameter which is about 1/4" (or slightly less) too small, which causes the lid to not meet the body/seal tightly. This causes the lid to rub against the hood pad (which it sort of does now with the correct filter).
Does anyone happen to know where to obtain the correctly sized air filter, or the manufacturer part number for one that actually fits properly?
C8AZ 9601-A or Motorcraft FA-50 should be the correct part.
From the parts catalog: 11.32 I.D. x 13. 30 O.D. x 2.80’ high
The closest I’ve found is the Fram CA324A but it is about a 1/4" too tall on my 1970 351C Cougar.
It measures 2.7-2.8" tall. That is better than being too short.
But it does make the air cleaner top rub against the hood insulation.
However, that may be due to the Ford Muscle Parts high rise D1ZX intake on this engine.
I haven’t tried a CA340 but it is 2.5" tall.
K&N makes a 13.25" x 11.25" x 2.5" tall round filter, E-1580
Some websites say Fram CA340A (current version of CA 340) is 2.5 inches high and some say it is 2.79 inches.
It appears Wix 42113 is 2.51 inches; also sold as Napa Gold 2113. Will pick up one tomorrow and see if it fits my 70 351C. What I have now is Wix 42116, which is too high at 2.82 inches.
I just measured the unmarked air filter in my 351C with original stamped steel air cleaner and it measures 2.75” tall. I’ve had problems with replacements being to tall as well, but 2.75 fits perfectly on mine.
The CA324A is also just slightly too tall in an original 1968 390GT air cleaner.
The Ford parts catalog also calls out a FA-50 air cleaner element for this application.
It raises the air cleaner lid up 1/8" to 1/4" too high also.
“I’ve seen those numbers too but on my '70 351C OEM air cleaner assembly, the CA340A is a perfect fit.”
Put some chalk on the top rim of your CA340A filter and then put the lid on. None of the chalk will transfer to the lid, showing that there is an air gap between the air filter top rim and the lid (I have the original air cleaner assembly on my 70 351C, too).
This is why Fram does not list our cars as using the CA340A. Fram says we should use CA324A, but that one causes the lid to be slightly high (as WCCC says their aftermarket filter does too): https://www.fram.com/parts-search/CA324A
It appears that no one makes an exact aftermarket replacement for the original air filter - WCCC says this, too. So the alternatives are to use one that is slightly high (as WCCC and Fram and Wix/Napa recommend) or use one that leaves a small air gap between the filter top rim and the lid, such as the Fram CA340A, which is not a good idea for obvious reasons.
I’m going respectfully disagree, at least a little bit. I took your suggestion just now and did an experiment. I placed some putty on the air filter element and set the lid on top. I used a bead of putty that was as thin as I could make it, about 1/16 - 1/8th of an inch.
When just resting the lid on the air cleaner, the putty left only a slight impression on the inside of the lid. However, when fully compressed by the wing nut, the putty was definitely compressed. If there’s an air gap there, it’s not a significant one.
I can’t abide the look of the lid sticking up with the other filter choices so I’m willing to continue living with this small risk. In any case, I’ve been doing so for years.
If you’d tried the test with chalk or kitchen flour, you would have proved that there is a gap. Even a gap as small as 1/16 inch (and I think it’s bigger than that) on a 13 inch diameter results in a total opening equivalent to about 2.5 square inches. Pretty good size hole to let unfiltered dirty air into the engine.
So there is good reason that Fram says not to use that particular air filter on our cars. But again your call. I’ll follow the advice of Fram, Wix, and WCCC and live with a tiny amount of raised lid instead. Wish there was an aftermarket filter that was exactly the right size, but there isn’t.
