AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

[Duane D.]

It is my understanding that the original AC-Delco A348C air filter had a horizontal square outer screen. I believe these were manufactured for the 78-79 model year of the C3.

My question is when did GM switch over to the diamond pattern screen? Specifically, what is correct for the 1980 Corvette. There are so many AC-Delco A348C versions out there. I have been told the diamond pattern filters are remanufactured filters made in Mexico, however I have purchased a decades old NOS sealed filter with the correct white script and diamond screen at a corvette show and am now being told it's not correct. Any help clarifying would be appreciated. Thanks...

[Tom R.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

This is taken from the newly revised and published 1973-74 TIMJG. References to the A329C filter remain, that the A348C replaced and used through the 1981 model year. Your photos shows the stamped service replacement A348C filter.

By late-1974 production (May-June) air-cleaner filter elements transitioned from the A329C to A348C for L48s/L82s. It is believed that no LS4 left the factory equipped with an A348C air filter.

The A348C filter is noticeably taller than the A329C filter but of the same diameter and retained the square-mesh featureBEST WAY TO PROTECT YOUR ENGINE - REPLACE WITH AC TYPE A348C. Original filters were misted with oil, which contributes to the yellowish appearance.

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[Duane D.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

Thanks Tom for your prompt reply to my question. I really appreciate the thorough explanation and photos illustrating the differences between the factory original A348C and the GM service replacement.

[Tom R.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

My question is when did GM switch over to the diamond pattern screen?

You raise a good question that I did not catch until I went back to review this thread after I had reviewed the revised 1980-82 manual. It lacks clarification on this detail but on the judging field, the rectangular mesh has been the accepted A348C filter of choice from 1974 up through 1981. When did AC Delco begin manufacturing the A348 in Mexico with its signature diamond, metal pressed screen? This should be clarified and should be directed to the 1978-82 team leader, Brian Pearce who is revising the 1978-1979 manual and responsible for the 1980-82 revision.

Specifically, what is correct for the 1980 Corvette. There are so many AC-Delco A348C versions out there. I have been told the diamond pattern filters are remanufactured filters made in Mexico, however I have purchased a decades old NOS sealed filter with the correct white script and diamond screen at a corvette show and am now being told it's not correct.

And they are (made in Mexico). But remember, there have been a number of iterations of the A348C not all consistent with your initial post. Later units do not even have the white letter on the black rubber.

[David L.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

I have a square mesh NOS A329C air filter with "BEST WAY TO PROTECT YOUR ENGING - REPLACE WITH AC TYPE A329C" labeled in white on the black plastisol part of the filter in a 1974 AC box.
I also have a diamond mesh NOS A329C air filter with "AC TYPE A329C" labeled in white on the black plastisol part of the filter in a 1992 AC box.
I assume that the 1974 version A348C AC air filter was also the square mesh type.

Dave

[Paul B.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

...I thought someone here who worked at GM one time said(maybe 10-12yrs ago, and I maybe wrong)that the square mesh style filters ended around the end of '79 production. Don't remember his name at the moment, but maybe 10-12yrs ago when I was having my 1980 Yellow 4spd car judged at about 4 NCRS events(one regional, three chapter) I was actively looking at every '79, '80 & '81 low mile Bowtie, Survivor type cars that I could look at. Saw about a 1/2 dozen '80 & '81 cars with less than 4,000 miles or so(for sale, Bowtie/Survivor judged)cars, not one that I recall had the A 348 C square mesh air filter. They had the "wire diamond mesh" style like your one pic shows, NOT the current diamond style that looks like it's diamonds punched out of a single band of metal. It'd be interesting if some ultra low mile '79, '80 & '81 owners out there, if there are any would say what their car has in it for an air filter. An '80 4spd car has more than a couple unique features that I don't think were ever included in the JGs, at least back then anyways. I sold the car many yrs ago, so I don't have any of the judging sheets to look at.

[Tom R.]

Re: AC Delco A348C QUESTION - SQUARE VS. DIAMOND OUTER SCREEN

I was actively looking at every '79, '80 & '81 low mile Bowtie, Survivor type cars that I could look at. Saw about a 1/2 dozen '80 & '81 cars with less than 4,000 miles or so(for sale, Bowtie/Survivor judged)cars, not one that I recall had the A 348 C square mesh air filter. They had the "wire diamond mesh" style like your one pic shows, NOT the current diamond style that looks like it's diamonds punched out of a single band of metal. It'd be interesting if some ultra low mile '79, '80 & '81 owners out there, if there are any would say what their car has in it for an air filter.

Talking to Brian Pearce, team leader for 73-82, and talking about this topic. the transition is the 1980 year from the square mesh to the diamond mesh, but a specific date/month could not be ascertained, which is not surprising. A couple of points to add and add context to the transition and that we learned from our study of the A348C and transition from A329C.

Air cleaner assemblies were shipped to the factory as an entire unit that included the air filter and label. Once in the bin, workers simple installed the air cleaner assembly without regard to the filter inside. Thus, the label always matched the filter inside the assembly. In 1974, our best work concluded the transition from A329 to A348 happened over perhaps a three month period as A329 inventory diminished. The point is there was no clean break and I would venture to say, the same practice happened with the change from the square mesh to diamond mesh screens. In fact, those workers probably had no clue there was a change to the screen mesh on air filters. Enthusiasts get to anal about these sort of things and we must remember this was factory work...keep the line moving!

What's correct for 1980? An A348C air filter in either mesh in a correct configuration, not the stamped diamond mesh not as Paul states.

Duane, your air filter appears to be correct but I would like to see a quality high resolution photo. Send to my email address.