Thoughts On Air Filter Size

tx65coupe

Active Member
Nov 29, 1999
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What size air filter should I get for my 65s 302? I want to get a KN Xstream with the lid that has a filter as well.

The HiPo 289 filter is 14x2.25 inches.

I would like to get a 2.5 to 3 inch filter. I have heard bad things about using a drop base. Is it true that it messes up the airflow?

How tall can I run without a drop base?

The 302 will have Edelbrock performer rpm intake and a 650 AVS carb with electric choke.

Also, I noticed that all of the KN Xtream kits come with a chrome base and a black top. That just looks weird to me since it doesn't match. I would like to get one that has a chrome top. I see they are available separately, but not in the kit. Does anyone know where I can get one like this?

This is what I am refering to.

K&N Engineering 66-3000 - K&N X-Stream Air Flow Assemblies - summitracing.com

K&N Engineering 66-1401XP - K&N X-Stream Air Flow Top Plates - summitracing.com
 
What's wrong with a drop base air filter housing? I use one and am able to run a 4 inch tall filter on a single plane intake manifold. You can actually tell the increase in flow by just using the air cleaner base as opposed to no air filter housing.

I find that trial and error works the best for me as everyone's car/engine configurations are always different.
 
I never thought that there was anything wrong with them before. They guys that are building my motor and the guys at KN both said it is fine to use the drop bases.

I have read on several forums that people claim it somehow messes up the air flow. I just thought I would ask.

What size drop base do you have?

Whats the configuration of your engine?

Do you think I can clear a 3 inch filter on my 65?
 
Be mindful of distributer clearance when sizing things up.
In a perfect world we would all be running velocity stacks with 4 open venturies, but good power can be made with a drop base. There are flow straightening gizmos out there that probably are worth a few ponies with rpm but are they worth the money? Probably not.
 
not all drop bases are alike, and they will not fit the same on all carbs either, I had to clearance mine (not sure what brand it is) a bit when i had the edelbrock because of the electric choke, as well the front lip because of the distributor cap clamp. But when I switched to the demon, no problems with clearances.
 
Thanks for the input.

I had a feeling that the drop base might interferre with the choke and the distributor.

My crate motor is coming with a regular air filter. I'll just wait until it is all installed before I make a decision or purchase a new air filter setup. That way I can take measurements.
 
I have to use the 2.25 element to fit under the shaker, but what I've found is that virtually all of the air is coming in through the top anyway. Maybe it's because I have the shaker though?? The top has dried out twice already and had to be re-oiled. The sides are still fresh looking.
 
Remember that 14" filter will not work with large distributor cap e.g. MSD on early sbf (289/302). You would need to bend+chop the body to gain about 1"
 
67rcks:
Remember that 14" filter will not work with large distributor cap e.g. MSD on early sbf (289/302).

14x3 High Flow Summit Filter, Edelbrock Air Cleaner, MSD Distributor.

DSC08441.webp
 
Currently I have an STP SA3648 which I believe measures 2,5" tall and have a K+N 14 x 3,063" filter ready to go when the paper one gets too dirty. I think the 3" is about as tall as I can fit under my '67. As for the air cleaner housing, I run the standard chrome lid dress-up unit you get at any of the Mustang parts houses. Not sure how directly that'll translate to your '65 though.
 
Thanks for the input guys.

jcp123,
I don't know how much differece there is in height clearance between 65-66 and 67-68.

Tim65,
My 302 is a 5.0 Mustang block, so I hope there isn't distributor problems with a 14 inch filter.

Are you running a drop base? If so, how much drop does it have?

That sure is a clean engine compartment. Whats the box on the driverside? I'm looking for some type of box like that to conceal my headlight relays and maybe a couple other things. Is it called a "bud box"? My Dad said people used to call them that.