Airbox silencer removal
 

I have an appointment this week to change my gears to 4.10, and I am all fired up to do something to my entirely stock GT. I have been searching the archives and found that removing the air box silencer helps the engine breathe. Does it help the car run better, and would just replacing the stock air filter with a K&N do the samething as a cold ait intake? I can't wait to start.
Thanks for your $.02
KG88GT

Removing the air inlet silencer is a basic, must-do 'mod'. Easy, quick, free and it helps engine breathing by removing an unecessary restriction from the air path. Installing a K&N air filter is also pretty basic and yes, it will also help performance by allowing better breathing.
Not quite the same as a 'Cold-Air intake' but frankly, close enough in terms of performance gain.

Both of these 'mods' will gain you about 5 HP over stock; most of it from removing that useless air silencer.

You won't 'feel' much difference in performance, other than a slightly better 'throttle response' but these help - and we all have to start somewhere.

The 4.10's will change the entire 'personality' of your Mustang and really help low-end performance. You will feel the difference!

Try advancing the timing a bit, too. 14 degrees BTDC is average. You'll have to switch to 92 or higher octane gas, but performance always has a price. Timing advance is a basic, free 'mod' and worth a tad better performance

Good luck.