PPCPete

I have a 1963 corvette with a 327 and a replacement intake manifold.
It has a stock hood. Does anyone know what Air Cleaner will fit under the hood? Replacement aftermarket air cleaner such as MR. Gasket or something from summit Racing????
It has a 4BBL Holley Carb 650cfm.

Pictures and or part numbers or spec. on hood clearance would be helpful.

Thank You!

Nowhere Man

You can start by telling us the make and model intake and carb

PPCPete

Its a Holly 600cfm 4bbl..with a Cyclone brand replacement intake manifold. ( #52001)

fredski

Not hard to find ,check summit or jegs ,they have drop down air filters that are lower . Also gm made this type In the late 60's .i have holly 650 double pumper elec choke on a eldebrock rpm manifold and fits fine on my stock 63 hood. Phone suppliers and explain what you need .
Must use a 3 inch high or 2/12 high available from KandN ( filter)
Fred g

DucatiDon

65+ factory drop base fits fine.

fredski

Summit racing part number ALL26092. Look up on line ,shows picture then you will understand . I have a gM version of this.

Fredski

Frankie the Fink

No matter what you cobble together check the hood clearance yourself before buying off on the changes. Tin foil and painter's tape work well.

Easy Rhino

Much better than using clay to check clearances.

65tripleblack

No good.

The closest point of contact is at 2:00 position if you look at the air cleaner lid from the back of the car, or through the windshield. The "tin" foil ***** should be positioned across and slightly ahead of the centerline, not fore-aft.

GearheadJoe

This is correct. The photo below shows the closest contact point for the stock C2 air cleaner and hood.

At first I was surprised that this happens on only one side, but the reason is that the entire engine is offset about one inch toward the passenger side.

Frankie the Fink

It was an EXAMPLE folks. I defend your right to put your ***** anywhere you like.

Im well aware of the "touch points" on these cars, chiefly at the rear of the PS dual snorkel extension tube when you try to put heat insulators under the carb.

GearheadJoe

I found another photo that shows the corresponding location of the interference (indicated by the blue tape) on the 1967 air cleaner. It is possible that earlier C2 air cleaners would have issues in other locations, but on my '67 this is the place where the air cleaner comes closest to the hood. On a stock L79 with the L79 intake and 3810 Holley carb, the hood clearance is about 3/8" to 1/2".

The OEM '66-'67 Corvette air cleaner assembly is a "drop-down" unit that is intended to provide good hood clearance. If you assemble the top and bottom sheet metal parts off the car, you will see that there is a pretty small gap (about one inch) between the lid and the opening for the carburetor throat, so this is close to becoming an air restriction.

Some aftermarket drop-down air cleaners gain additional hood clearance by further reducing this gap. It would be a good idea to check this gap prior to installing an aftermarket drop-down air cleaner. There's no sense choking the air flow to the carb just to get some extra hood clearance.

Blk63Vette

I'm with Frankie I feel you have a right to put your ***** where ever you want!!

65tripleblack

Hi Joe,
You may already know this, but there is a limit to how much drop can be designed into an air cleaner before air flow problems negate the effects of a larger air cleaner height. The culprits are the vent stacks, and if they are less than about 3/8" below the underside of the lid, then float bowl reference pressures are affected and starvation problems can develop at high airflow rates. Doesn't matter much whether the tubes are angle cut or not.

GearheadJoe

Hi Joe:

Thanks, I did not know that was another limiting factor with drop-down air cleaners. My guess is that the stock C2 air cleaner probably pushes this parameter to the limit as well.

I recall talking to a guy who did a chassis dyno test on a car that had an extreme version of a drop-down air cleaner. Simply removing the air cleaner lid added about 25 HP. I suppose that the difference could be due to restriction in the air cleaner element, but I bet most of it was due to the low height of the lid.

65tripleblack

That would be my guess as well; his A/F might have gone lean for the reason mentioned. I did cut about 1/4" off the vent stacks on my QF carb to obtain the minimum 3/8" clearance!

I would say that hif filter was not a new one, or was restricted in some other way. Was it a 14" x 3" paper element as stock 1966 up SBC? I modeled my engine as is (14 x 3) vs 14 x 4 using EA Pro 3.5 and produced a negligible difference across the board. The difference obtained by cold air induction (no ram effect) was dramatic, as I fully expected..

65tripleblack

That would be my guess as well; I did cut about 1/4" off the vent stacks on my QF carb to obtain the minimum 3/8" clearance.

I would say that his filter was not a new one, or was restricted in some other way. Was it a 14" x 3" paper element as stock 1966 up SBC? Check his A/F ratio plot if he has one. Possible the mixture might have gone leaner than it normally does on the top end due to this exact phenomenon and/or dirty filter. Our friend the Duck recommends Baldwin filters.

I modeled my engine as is (14 x 3) vs 14 x 4 using EA Pro 3.5 and produced a negligible difference across the board. The difference obtained by cold air induction (no ram effect) was dramatic.

GearheadJoe

The story about the 25 HP loss was just something a guy mentioned to me in conversation, so I don't know the specifics of the air cleaner that was involved. I do recall that he was convinced that the problem was a very small clearance between the lid and base of the air cleaner. It was an aftermarket dropped-base air cleaner that had probably been optimized for a low height, without regard to possible consequences of dropping the lid too far.

65tripleblack

Before I decided to use a GM drop base air cleaner, I was looking at aftermarket choices. As with anything else in life, once the lemmings begin to "pile on" to a good idea, the exploitation and grotesque results quickly spin out of control. I was looking at "spun aluminum" drop bases which may no longer exist, or was gobbled up by another snake oil aftermarket conglomerate. I decided not to buy their product after taking measurements and finding that there would be clearance issues on the upper end. The "spun aluminum" base offered a "drop" just about 1/4" more than the stock GM Corvette drop bases did. This would have caused interference with my carburetors' bowl vent stacks...............putting them just about flush with the underside a stock Chevy Corvette 1965-up BBC/SBC lid. As I said earlier, I had to cut down the stacks on my QF carb, which, incidentally, are probably designed with extra length and shortening allowed to tailor to varying air cleaner lid clearances. Looking at a Holley carb from the era, the stacks are lower than those on the QF. Set to less than/equal to the min clearance required which is about 3/8" when used with a stock drop-base air cleaner.

Dave64

Roger that. Who doesn't have a mark on their hood in this spot ?