The stock heads and exhaust manifolds are also capable of supporting more HP than our stock motors provide, yet swapping them out for better ones will increase power. I believe volumetric efficiency starts to come into play.
It seems to me that in a N/A application, the amount of air the motor consumes is determined by the pressure differential between the vacant cylinders and ambient air pressure (aside from displacement and RPM) and resistance in the flow path. As a system, this is expressed in terms of Volumetric Efficiency, or a measure of the engine's ability to fill its cylinders. Given a finite and constant resistance in the flow path, you have to increase the pressure differential to increase the air flow (push harder on one end or suck harder on the other). Anything you can do to decrease the resistance in said path should increase the flow, given the same difference in pressures. Which as I see it, is the basis behind head flow testing at a consistent pressure differential. It would seem logical that a reduction in resistance would result in less pressure differential required to achieve the same amount of flow...at least that's how I understand it. As with everything, I'm open to, and welcome, any explanations that support a different theory! In other words, I'm not trying to call anyone wrong, just trying to use Physics to think this through.

Here's an interesting comparison on air filters. It's either true, or a lie perpetrated by the magazine to support the sales of their advertisers (which is a distinct possibility but highly unlikely, IMO).

FOUR WHEELER Magazine's Project M.P.G.

 

I don't know anyone that would run a 400 hp sbf with the stock air box , you will never get enough air in my opinion....Lew

 

I have one one my truck and I like the ease of maintenance. Only thing I dont like is have to wait for the dang thing to dry. Things don't dry fast on the near the Texas coast lol. I would look into the non-oiled ones that you could clean. Airaid has one but I don't know much about it.

 

Take a look at the Amsoil Ea filter. Reusable but not an oiled filter. I have seen many vehicles driven in dusty conditions with a K&N with HUGE silica spikes in the oil. Silica being an indicator of sand/dirt.

 

Do you have one on your truck? I would like to know how well it works and if it easy to clean.

 

No but I do have one on my mustang and in my wife's car and they work great,

Cleaning
Ea Air Filters should be cleaned every year or 25,000 miles, whichever comes first. Carefully remove the filter from the housing. Clean the housing with a shop towel, being careful not to knock contaminants into the air inlet. Filters can be cleaned by carefully vacuuming the filter media on the dirty side, or by holding the filter with one hand and carefully blowing the filter media at a 45-degree angle on the clean side using low-pressure shop air (15-20 lbs. psi).

 

AMSOIL Ea Air Filters - Nanofiber Technology

 

sounds like any reusable filter would be good. I see the cheapest being one from summit and S&B

 

Does it come all the way clean when you vacuum it or blow it off? The k&n on my truck does not come all the way clean nor does the one on my mom or dads truck. I have been considering the one by afe for a while now but I can not find where it says how many miles till you clean it. The amsoil and the afe apear to have the same description but the amsoil looks like a regular paper filter and the afe looks more like k&n. The aft says its washable it does not say anywhere how you clean it. I still dont know what to get. I will do some more research.

Its whatever you prefer. Those are the cheapest sites I also found.

 

Nah it's not paper is a micromaterial. A lot more dirt road friendly. It comes pretty darn clean. It doesn't need to be 100% clean to do its job.

 

The K&N and AFE you just use some water and soap , scrub it clean and hose it off , water won't hurt them ....

 

I think I will give it a try. Thanks for your help.

I use dish washing soap and a water hose to wash it off but it is still pretty nasty. I will try to scrub it if I dont order the amsoil one.

What filter did you decide on Wicat3?

 

A family member bought me a drop in K@n for my birthday,so I figured what the heck,why not try it out? I did notice a little better throttle response,and the engine does seem to breathe better at full throttle with(which I seem to be at often with the 5.0 and taller then stock tires and needs a re-gear,and lots of 2 lane roads and slow drivers around here). But my truck also has headers and a full exhaust,so maybe that makes a difference also.

 

With the K&N oiled filters you need to use hot water and soap to cut though the oil , as hot as you can get it from the sink , never tried it but a dishwasher might do a nice job , just don't tell the wife or GF......

 

I never used hot water. I've always used the water hose. I will try that. I would never hear the end of it if I put it in the dishwasher . If someone trys that please let me know how it works lol.