Pontiac OEM Air cleaner lid....ever seen one like this?
 

I don't remember seeing "slots" like these in any air cleaner lids....is this a factory deal and I've been hiding under a rock, or did someone add these? Reportedly from a "76 Grand Prix 455". Trouble is, I'm afraid it's a "one off" and I happen to like it, from the style to the functionality... as a way to get more air into the carb....

Been in playing with Pontiacs since Ollie North testified…

I’ve never seen nor heard of such a lid, until your photo.

It’s nicely done.

Not factory issue though.

Hmm ... VERY nicely done. Like someone rigged it up on a rotary table on a milling machine.

What do the edges of the slots look like? Cut, or stamped? If it's stamped I seriously doubt it was a "DIY" project. If it has fairly sharp edges with no light radius on the edge from punching then it was probably done by a talented, well equipped DIY'er.

I don't know...wish I did. Was trying to buy it from the guy selling it, and he was such a complete and utter buffoon, he thought I wasn't interested after telling him It was "perfect" and "I wanted it."...he sold it to someone else.

If I had to bet a lot of money ... I'd say it was done in a "factory" environment at least. I think I can see a rolled edge from a punch, and I can't imagine an off the shelf punch and die with just the right size and radius .. that would also fit in that cavity. However it also wasn't punched before the lid was stamped, no way the sheet metal would hold up to stamping with the slots already punched.

Could have been done at the same time as the stamping, but that would mean it would have to be "factory" or done by a sub-contractor at least.

Makes me wonder if it was some oddball police package part, or obscure aftermarket piece.

If it was for sale from either the Detroit area, or a place like Washington state close to Boeing etc. .... lots of people with access to lots of high end shop equipment back in the day producing things with company equipment for their own projects.

https://forums.maxperformanceinc.com...8&d=1712808890

It's hard to say when it was done. If you do a punch that close to a bend line, it would distort the radius when forming. It looks like that is happening, as the corner at the bottom next to the radius is shaped differently from the opposite side. If you machine after the fact, it would probably give a more uniform on the end of the slot.

Keep in mind that a lid with slots like that would allow cool air to bypass the vacuum dashpots that close when cranking the engine cold, so it would possibly negate some of the emissions hardware.

Definitely a bit more than a guy in his garage with a die grinder :)

I can't see that being a factory part. Pontiac was just getting over the emissions problem of 1973 and I am sure the EPA would have really come down on them for this. As was mentioned, it would negate the thermostatic controlled air inlet. From what my dad was telling me, he worked at GM Research in the Emissions Lab during the 70's and 80's, GM was doing everything to comply with Emissions standards put forth from the government. That lid would have been a defeat and frowned upon. If they needed to get more air, they could have done what Chevrolet did with the Corvette, twin snorkels with the thermostatic diaphragms. I think 77-79 Corvettes got the 2 snorkels.

I think I recall Air cleaners modified like that on early NACAR engines

I'll second that!!!

Agree, 3 votes for that nascar mod.

TV

That would explain a lot, OEM part, smart people, lots of resources.

Nascar has used cowl induction hooked by a duct/ducts to the firewall at the base of the windshield since at least the mid 60s to take in high pressure cold air. Cutting holes in the lid would defeat the high pressure from the windshield base, causing a ram effect into the carb.

Below is Smokey Yunick's # 13, 66 chevelle, BBC air cleaner assembly:

https://i.ibb.co/PGLGJYp/yunick-66-chevelle.jpg

For the ford lovers a 1964 galaxie Nascar air cleaner assembly:

https://i.ibb.co/2ZPDGCb/1964-ford-g...3253138966.jpg

Nascar has been using this style of air cleaner assembly for at least 60 years.

I don't think that was a factory issue for any Pontiac, but going from memory I think I may have seen one in the 70s, 80s on a medium duty chevy truck with a BBC. Since the medium duty trucks had no drive by noise requirements, or smog provisions having to use exhaust stove heated air to pass emissions during that time period. Someone just cobbled some junkyard parts together, and they ended up on a 70s GP would be my guess...........:noidea:

How about this Nascar mod :D

Attachment 631940

The "factory" aluminum SD tripower from about 1961 (memory can be hazy, and too lazy to look) had seven openings the same size as the opening for the snorkels. Somewhere around here, and don't ask where, I have a stencil with the correct spacing for the tripower version.

The tripower version is pretty scarce, I can only remember seeing one.

I know nothing about one punched for either a single quad or dual quad.

Jon

I'll weigh in. I understand the concept of the slots. I have access to a complete welding/machine/fabrication shop that has helped me immensely over the years. (I used to work there, still friendly with my old boss. never burn a bridge). The shop has everything you could think of Amada brake presses, shears, turret punch presses, lathes, saws, plasmas, laser cutters, From a Cincinatti 300 ton press down to a Beverly. I think a CNC Bridgeport could do that but it would be one heck of a program. Could be a NASCAR part but still... how did they do it? I think one company somewhere (not GM) did it for the aftermarket. I think it was stamped in before being formed. I had another friend that worked at Art Kraft Machine in Langhorne, pa that could have did something like that.