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Stealth Aluminum Intake
How to Modify a Common 429 Air Cleaner Base
into a Ram Air version to work with a Stealth Aluminum 429 SCJ Intake Manifold
429 Group member Dan Schott recently decided to change from the factory cast-iron 429 SCJ intake to the aftermarket Stealth Aluminum intake for a weight save and performance increase for his car. However, one of the technical challenges in doing this installation is dealing with the height difference. Dan found the Stealth intake, as installed on his engine, was 1.5 inches* taller than his factory intake. This added height raises the factory ram air air cleaner 1.5″, making it impossible to use without interfering with the underside of the 71 Mustang ram air hood. Taking a cue from Robert Myhrer, who ran into a similar problem using the Blue Thunder intake, Dan set out to modify a more common 429/460 type air cleaner base (instead of his rare, original 429 SCJ ram air unit) to gain an acceptable underhood fit with the Stealth and still maintain the appearance of the factory 429 ram air unit.
For a starting point, Dan found that some of the air cleaner bases used from 1970 – 73 on the 429/460 Lincoln/LTDs were dimensionally the same (17″ outer diameter by 3″ tall) as the original 429 Mustang ram air unit. Additionally, these standard bases also had the holes for the charcoal canister hose and valve cover breather hose in the right location and also the same underside indentations as the factory 429 SCJ ram air version. With these key features all the same, Dan had the correct piece to begin the two key modifications he needed ; 1) Lowering the air cleaner housing -vs- the mounting around the carburetor; 2) Adding a metal lip to the top edge of the air cleaner for mounting the rubber ram air seal. The table below shows pictorially what you need to look for in your 429/460 style base;
* Note: Those doing this project are encouraged to verify the exact height they need on their own cars since vehicle to vehicle differences, carb types and different versions of the Stealth Intake may change the 1.5″ dimension to a higher or lower number.
Update on 3/11/05
Dan sent in these new photos showing the completed installation of the Stealth Intake. Dan painted the intake Ford Blue to maintain the stock appearance.
Completed views of installed Stealth without air cleaner installed
This photo above is of a heat shield Dan fabricated to work with headers allowing him to still have a location to connect the hot air tube to.
Before and After Photo
Here’s a good A to B comparison showing the factory setup at left versus the final Stealth setup at right with modified air cleaner.
Completed Stealth – passenger side view
Completed Stealth – driver’s side view
1.What You Need in the Base You Start With
Here are the dimensions and features you need in the standard 429/460 base you start with in order to match up with a factory 429 CJ/SCJ Ram Air cleaner when you finish. Look for a 70 – 73 429/460 Lincoln/LTD type air cleaner base, but use the pix below to verify the correct features are present since we’re not sure all 70 – 73 429/460 Lincoln/LTD were the same design.
Note: Unfortunately, we were not able to take photos of Dan’s original standard 429/460 air cleaner base before he started his
modifications, so we are using the photos below of his finished Stealth air cleaner since these photos still show the key
features to look for in the “standard” 429/460 air cleaner base you will need for this project.
17″ Diameter
3″ Height
Three underside indentations in these locations
Correct passenger-side locations for charcoal canister hose and valve cover breather (just behind snorkel opening)
The photos above show a side by side comparison of the factory 429 CJ/SCJ Ram air base (blue) to the standard 429/460 air cleaner base (bare metal)..
2. How to Lower the Outside portion of Air Cleaner versus the center Carb Mounting Piece
From this “base” starting point, Dan cut the center donut portion that surrounds the carburetor separate from the air cleaner, then added a 1.5″ high by 11″ diameter ring of flat steel stock. This was welded in to lower the outer portion of the air cleaner base versus the center portion that rests on the carburetor. This step essentially lowers the air cleaner base the 1.5″ needed for hood clearance.
Views from top of added 1.5″ ring
Views from bottom of added 1.5″ ring
“Donut” portion to be cut from top
3. Adding the Support Ring for the Ram Air Seal
Since the standard 429/460 air cleaner base has no provision for a ram air seal, one must be created. To do this, Dan fabricated a steel ring to support and retain the the ram air seal. This ring extends approximately 1/2″ beyond the outer edge of the air cleaner. This ring was then welded to the top edge of the air cleaner base.
This photo from the top also shows the ram air seal ring and approximate 1/2″ dimension.
This photo from the bottom shows where Dan welded a metal ring to the outer diameter to create a support ring for the ram air seal. It extends about 1/2″ from the side of the air cleaner.
4. Photos of the Finished Product
The final steps of the project (not shown here) involved grinding/finishing of the metal and painting the unit Ford blue and finally adding a repro rubber ram air seal. Dan now has a 429 Ram Air cleaner that looks just like a factory unit AND will work with the added 1.5″ height of the Stealth Aluminum intake manifold!
Installed Photos of the Stealth Intake and Dan’s Modified Base
Additional Notes from Dan
- For my set up, I am using a 3.5″ tall air filter.
- To make sure I would get good airflow to the carb, I made sure I had approximately 1″of clearance from the underside of the air cleaner lid to the top of the carb air horn. To get this clearance, I will be adding a 0.25″ high spacer ring between the bottom of the air filter and the air cleaner base. To make this spacer, I just cut the bottom rubber piece off an old air cleaner element.
- With the modifications to the air cleaner shown on the page above, I have approximately 0.75″ – 1.00″ of clearance from the top of the air cleaner lid to the bottom of the hood with the .25″ spacer ring in the bottom between the air filter and the base (Note: I will supply final dimension once reassembly is complete), so there should be no banging of the lid into the underside of the hood ( let’s hope!).
- The Stealth intake I am using has the SCJ Holley type flange pattern – not one with the CJ Q-jet flange.
- I did shave a bit off the top of my throttle cable bracket and lowered the throttle cable mounting bolt hole just to make sure it did not hit the bottom of the base. That worked fine. No clearance issue there.
- The Stealth intake ports are close to the same dimension as the stock CJ/SCJ head port.
- Some 429 aluminum intakes on the market have the smaller standard head-sized ports that would require “opening up” of the intake port in order to port match the intake to the CJ head port. That’s why I went with the Stealth – no port matching necessary!
- Completed, assembled pictures to be added once everything is back together.
A Big THANK YOU to Dan Schott for documenting his project to help others who might also want to add a Stealth intake to their engine and maintain the factory appearance of their air cleaner. Also, a Big THANKS to Tom F. and Brian R. for their help to Dan in building the new base. They were instrumental on this project and their knowledge, skills and time were greatly appreciated in helping Dan get all the fab work done!
