With the Drag Pak'd T/A scoop on my Challenger being so big, it occurred to me that I might want to do something to keep the air entering the scoop from "slamming" into the air filter and/or causing buffeting or other airflow disturbances that could impact the carb's operation.

I found some different styles of air deflectors, a couple of which are shown below, that I might be able to adapt to the plate that seals the carb to the hood and might help w/ what I'm concerned about.

Does anyone else think this could be something worth testing out when my junk's finally back at the track? Thanks - Brad

Two of a variety of different styles I found:

Hmm, I just don't know.
Wonder if the DP racers are doing anything like that.

One big difference is that they're EFI, which the late Monte Smith said was much less sensitive to airflow over the top of the entry.

I always thought a deflector like you're thinking was more important without an air filter. The filter itself does a good bit of "turbulence straightening".
The "deflector" pics you posted above are what I see on dirt track cars where they're just trying to keep mud from getting caked up on the air filter.

It depends on the diameter and how tall the air filter is, doesn't it
All the air has to go through the filter no matter what the throttle position is, correct?
I wouldn't try fixing it until I knew is was broken

Same here. But I'll be working w/ a wideband O2 setup for the first time, and will be looking for anything odd as far as air-fuel #s going bonkers at high speeds when there could be a lot of "activity" inside the scoop.

All in due time...

BradH? I have been thinking about running this hood & scoop on my 70 Challenger if I don't go with the shaker hood. Could you get me some measurements of the location, height, wide & length of the opening for the scoop? I am wondering if it will even clear my tunnel Ram with 2 Dominators on my Hemi or not? Thanks.

I was working on a 6x21" for over my blower and was told 1.5 to 2" space in front of the filter on the front edge and the rest can be exposed.[speedtalk.com]

My hood is a one-off done by a local (to me) fiberglass body person. It started out as an older reproduction T/A hood, then I decided I wanted about 1.5" additional clearance and my "glass guy" modified the original hood & scoop per my guidelines.

The closest thing I've seen available as any type of production item is VFN's 5" T/A scoop added to their standard Challenger flat hood. A couple of people on here (either currently or in the past) have that hood & scoop combination, including the car in the pic below.

Okay, thanks. Yeah, the VFN's 5" T/A scoop hood is what I was thinking your hood was & will probably be the hood I may order?

I'd try it as is because you already have a bit of height in your favor by the design of that scoop...........like the 6-pack, you have a wall/lip at the base of your scoop and I totally trimmed mine like a Hemi scoop and needed a dam about 1/2 up the filter to clear up WB readings and smooth it out.........

I might be able to adapt to the plate that seals the carb to the hood. Have any pics of said plate that seals the hood?

BradH? I have been thinking about running this hood & scoop on my 70 Challenger if I don't go with the shaker hood. Could you get me some measurements of the location, height, wide & length of the opening for the scoop? I am wondering if it will even clear my tunnel Ram with 2 Dominators on my Hemi or not? Thanks.


I have this vfn hood I can get measurement if you need them.

WRT "much less sensitive to airflow over the top of the entry"

True, that. An EFI entry doesn't have the extremely sensitive air bleeds in the air horn, and no booster or venturi responsible for the controlling vacuum signal.

If the A/C interior volume (diameter inside the filter element X height) is big enough like 14" X 6", the air will be slowed & straightened passing through the filter, and IMHO no mods to the scoop are needed. There's no such thing as a too-big filter can or scoop interior (unless it significantly increases drag). The ideal volume is tunnel ram plenum size. Look at the Harwood stuff.

Relevant and not mentioned: the scoop's open area is sized for the highest MPH the car will see, be it 1/8", 1/4 or Bonneville, with highest MPH needing the smallest entry.
A tractor pull needs a wood chipper entry (big power X low MPH = large scoop), a 300 MPH LSR needs a mailbox (big power X high MPH = small scoop).
The Chrysler factory "Baughman" pro stock scoop is a lot smaller than you would expect.
In real world terms, a hot street car that may never seen 125 MPH in anger needs a larger scoop than the same engine in a 1/4 mile car.

Here's how I constructed my air pan before attaching it to the scoop.

Honestly I think the opening is too big. I would make some kind of reverse lip inside the scoop at the bottom edge. Maybe 1.5" so you don't get that turbulent air off the hood surface . It will give you "clean" air.

RacerX, If you could get me those dimensions whenever you get a chance that would be great. No rush. Thanks.

Will do.

I can probably dig up something. The last one was made of a luan panel from Home Despot, with a cutout in the center where I attached the base of a 14" air cleaner so it fit the carb nicely. Then I glued the fire-retardant (resistant?) foam that Moroso includes w/ their air pan kits (can be bought separately, too) around the perimeter. The closed hood held it down because I did multiple rounds of test-fitting to keep adding layers of the foam until the fit was "just right" with the hood down.

It wasn't pretty, but the car picked up .1 ET and 1+ MPH vs. the same scoop w/o the carb sealed to the hood. Also, the old one was a good bit bigger than the new hood requires (different brand hood and the opening wasn't sized like a real T/A hood) and it was really obvious when you put your hand on the top of the hood after the car was running where the wood acted as a heat barrier vs the temp of the hood exposed directly to engine heat.