I purchased an L88 repro hood from J&D Corvette for my 72 this weekend and have a few questions.

When I purchased the car, the previous owner had already deleted the wiper door and installed a longer hood. To get the same length hood in the L88 style, I had to purchase the '73-'76 hood. Fits pretty well for the most part, but no longer features the wiper tray grill like the old hood did. Should this be a concern in terms of functionality?

Secondly, the scoop on the distal end of the hood is completely glassed in. Weren't the original L88 hoods vented? If so, which panels should I knock out to vent the hood the way it was intended? Are there grilles or anything available to prevent it from being just an open hood?

My apology for the crappy blackberry picture!



Thanks.

 

the hood scoop should be open at the base of the windshield. Does the hood have the airbox that fits over the L88 style air cleaner base?

 

Yep, the real L88 had a backward facing scoop that faced the window. The idea is that there's a high pressure area there that forces air into the scoop. The original L88 hoods had a plenum chamber. There was a hole in it that matched the air cleaner base. (The air cleaner base was the same as sold on other Corvettes, except you didn't get the upper part of the air cleaner (the lid). Used to be you could buy the plenum chamber part seperately to glass it in seperately with the end result of having a duplicate of the factory L88 hood. I'm surprised J&D doesn't sell the parts to allow you to construct a duplicate factory L88 hood.

PS: Looks like your hood fits nicely. That's not always the case with a repro hood.

 

Just to be clear, the open portion of the hood is close to the base of the windshield and NOT the area shown in your image.

 

I had a few of these questions before I ordered mine. My question was, if I am sitting in the drivers seat, can I see the air filter thru the windshield into the cowl opening.
Some aftermarket hoods are closed off, some are not. The one I got is open as described above and I can see my air filter. So I am happy.

 

There's an up and downside with the hood open in the rear. Upside is the car tends to run cooler because the underhood heat escapes, downside is cabin temps can be warmer because some of that heat tends to be drawn into the fresh air intake at the base of the windshield.

The engine running cooler part outweighs the somewhat increased cabin temps in the 68.

 

So in answer to your Question its No and Yes. The Hoods that came from the General had the forward Scoop that You Pictured Closed just like Yours. The Hood Vents Air to the Carb from the Windsheild because this is a High Pressure Area when at Speed. So why the forward Scoop? Its because this is a Low Pressure area and Yes its suposed to be Cut out. When it's cut out ( the vertical portion inside the scoop) it will Vent Air from the Radiator and up and out of the Engine Compartment. This helps Three C3 problems. Big Block Radiator Air Flow High Temps, Engine Compartment Temps, and the Dreaded C3 Lift at Speed handling Issue. Look at any C5-6R thats raced in Lemans in the last 7 Years its the same design 30 Years later. So cut it out, well that is unless your going to use it on the Street where Water is going to run in and Your probably not going to see the high speed advantages. Keep in mind that the Hot Air from the forward Scoop just might find its way back down the Rear one. I have never seen one of these Cut out. If Your Hood dosn't have the Air Chamber, the part that is on the underhood side and chanels the Air to the Air Cleaner, I have one I could sell. The People who sold it to You should be able to provide one to. Keep in mind that this will require a L-88 Style Air Cleaner all of wich is avalable aftermarket. You may wonder why you didn't get one in the first place a lot of people don't want one. If the Hood had one bonded from the Factory and it dosn't fit your Air Cleaner right there isn't much you can do. If You bond it in place for Your Car you can make it fit just right.

 

I have the vents cut out of my big block/LT-1 hood.
Since there is no bezel for those vents on the L88 hoods, it might be hard to make it look "clean" or like the vents were there from the factory.

(without bezel)


(with bezel)

 

Here's a shot of the underside of a long hood with an area cut out.



In addition to this cutout, you'll need the L88 pan, that GM bonded to the underside of the hood, and it mated to the bottom half of an air cleaner base. I don't have pictures of mine, but you can use a regular 14" air cleaner with base, filter and lid to hold the L88 pan. You then use fire resistant foam strips around the edges where it mates with the underside of the hood.

Hope this makes sense.

Mike P

 

Vented? No. Functional. Yes. An air box was bonded to the underside of the hood which drew intake air from the area at the base of the windshield.

Not the best pics for this purpose, but you can see the air box bonded to the hood.

 

Airbox install on a 1973 L-88 hood.

Marty.

 

Here's the airbox mounted on the bottom of a regular air cleaner.



This is a reproduction of the L88 airbox for the 68 & 69 cars.

Mike P

 

I take the chance of this thread to focus on a "issue" related to cold air induction.
with my car ( L88 clone engine +CAI ) i have experienced that carburetion largely depends from air temperature and humidity. since fresh air is drawn , just few deg in air temperature can affect -badly- the engine operation , forcing to readjust idle mixture screws to have the right idle speed and when extreme variation ( from spring to summer) also overall carb tuning. an open element air cleaner in an enclosed hood instead uses already heated air that is quite stable at temperature, so no change in carburetion. So , i think, if the user wants an easy , usable car without carbuetion issues, better to stay away from CAI , unless performances are the first target

 

Good point. The original L-88 hoods were supposed to be used on cars which were being tuned for the conditions you point out before each race.

 

Are these the hood vents that would be used if one were to punch out the slots at the front of the hood?

http://willcoxcorvette.com/product_i...ducts_id=25887