Help with air cleaner service decals?
 

Hopefully I can get some information to help me figure out what I have. My car is a 1967 Grand Prix, and a side project I've been tinkering with is restoring the air cleaner. The air cleaner that came with the car (That I believe to be original) was stored in the trunk and as a result has some rust issues so I picked up another similar air cleaner on eBay, however the "new" air cleaner seems to be the optional Heavy Duty variant but I cannot find a whole lot of info on either. Another problem is that I haven't found a reproduction decal for either which would be an issue. What would be the best way to make sure the air cleaner would be correct?

Much appreciated,

Jonathan

Really can't say for sure but looking at the Engine Option page from the 1967 Deluxe Brochure,
shows the 360 HP 428 which appears to share the same Breather as the GP 350 HP offering.
I would think the 428 used the HD filter.
Just a guess.

https://live.staticflickr.com/65535/...35a57993_h.jpg

Side by side they look very similar but the HD definitely takes a different filter. I'm not going for a super high level restoration but I would like to be correct where I can

The HD and regular air cleaner assembly are identical (apart from the label), all that HD meant was that it came from the factory with a filter element that also had an oil soaked foam outer.

Some years back I purchased what I thought was the correct air cleaner for my 67 428 non HO Bonneville., The build sheet indicated that my car came with a HD air cleaner. It was the same one you posted. the HD taller version. I say taller as compared to the correct for the 428 4bbl non HO slimmer profile chrome lid version which I recently acquired after a long search.

I was told by many that the 428 4bbl non HO cars in 67 only came with this slimmer air cleaner and it only fit the Quadrajet carb while the 400 cars came with the Carter carb which fits the taller air cleaner you have shown. The taller air cleaner never fit my Quadrajet while the other does. If you have a 400 in your GP I would think that air cleaner you show is correct for your car. If I recall that sticker is not reproduced but you can always find a good artist/graphic designer to replicate it.

Its interesting in the photo of the brochure that you see the slimmer version on the HO motor while almost every 67 428 HO car I have seen has the open air cleaner.

Something else that stands out is on my window sticker its called a dual stage air cleaner and on the build sheet its a HD air cleaner, see pictures. Guess GM didn't settle on one name for 1967. I also posted a side view of the slimmer profile 428 4bbl Quadrajet chrome lid air cleaner.

I’ll have a look tomorrow at my MPC to see what all the different part numbers were in 67 for air cleaner assembly’s

Thank you for the info! It's reassuring to hear that at least what I have is correct for the car, I'll have to look into finding someone who'd be willing to recreate the sticker.

Just hit the MPC, 67 was quite the year for air cleaners at Pontiac! Well over 30 different part numbers for air cleaner assemblies and that’s just for 4 bbl’s!

Restricting things to just B bodies cuts it down to 10. What creates so many variations this year is the factors of having a closed crankcase set up or not, having a smog pump or not (you could have closed crank case or not without a smog pump but all smog pump cars had the closed crankcase vent set up) along with HD filter or not and engine variety. They cleaned things up big time in 68, from about 35 to 5!

So for big cars only (remember that air cleaner assemblies were sold complete with lid and air filter element.;

400 4bbl with no smog pump and no closed crankcase system you had 6420972 for the standard air filter and 6422849 for the HD oiled filter element.
(These we’re carry over from 1966)

400 4bbl with no smog pump but with closed crankcase system you had 6423212 for standard and 6423213 for HD filter. (These we’re new for 67)

Next was 400 4bbl with smog pump (and closed crank vent), 6484472 for standard filter and 6424505 for HD filter. These were also new for 67.

Next is 428 (not HO, not 2+2, no closed crankcase), 6423207. Then 6422168 is same application but for the 2+2, chrome plated (Also 6422168 is the same number as the non HO non smog GTO). Both are new numbers for 67 but the chrome one has a number that indicates 66 vintage but the exact number is not used previously.

Next comes 6484473 which is for all 428’s (HO and non HO) with smog pump and or closed crankcase. No mention of chrome or not but price would indicate yes and as mentioned all 428’s were supposed to have chrome dress. These are new for 67 numbers.

Lastly is 428 HO without smog pump or closed crankcase, 6424590. same part number as 400HO GTO with the same lack of smog pump or closed crank. Again, a new for 67 number.

Note that no HD filter options were offered on any 428’s.

I think it breaks down like this visually…

All 400 4bbls used black closed small diameter snorkel lids

Non smog 2+2 (except HO) used the GTO 4bbl chrome pancake style air cleaner.

All non smog, non closed crank case 428 HO’s used the open element closed lid air cleaner.

All other 428’s (with smog or closed crank) used a larger diameter snorkel chrome lid air cleaner.

Oh my I had no idea there were so many different variants! Fortunately it looks like the HD air cleaner I have matches the engine configuration I have on my car, although what's the difference between a closed ventilation system and an open one? I recall the engine has a PCV valve near the distributor but there is also a breather on the valve cover, is the breather what makes the system "open"?

Edit: I think I understand better now, I found a picture from the manual which cleared it up

Open meant a breather on the valve cover rather than a tube linking the valve cover to the air cleaner like all 68 and up cars.

My understanding is that the smog pump (called A.I.R.) and the closed crankcase vent were mandatory on California cars but the closed vent was also a stand alone option on 49 state cars.

The HD filter air cleaners were identical to the non HD version other than the different filter element and the info stenciled on the housing.

Leave it to GM to have a dizzying over 30 confusing array of air filters like that. Talk about ridiculously redundant. Fantastic information and thank you for sharing.

North, you indicate no HD air filter option was offered on any 428 in 1967, yet my build sheet and window sticker photos show one. Any information on that?

Mark, my mention of no HD filter option is based on going through all those air cleaner part numbers. The only mention of HD was on the 400 applications above. There could be mistakes in my MPC, I doubt it was due to part eliminations as my MPC was only printed two years after the last 67 production.

Perhaps if you ordered HD air cleaner on a 428 they just gave you the 400 4bbl air cleaner? Is your 428 and HO?

Thanks for the info north, I think I'm able to make sense of what should be correct in my application. Whichever direction I go at least I know both service numbers and decals that I have would be correct (6422849 and 6420972). Also, what is the MPC that you mentioned, it sounds like a valuable resource.

Cheers!

Master Parts Catalogue. I’m using the November 1969 edition.

My car is a 428 4bbl non HO.

As always you are a fantastic source of information and facts John.

It’s the MPC, not me ;-)