I just installed a Flowmaster 40 series muffler on my 1992 f-150 with I6 engine. I went with the 40 series because it is the loudest flowmaster there is. The only problem is that it's not loud at all! It definitly has a deep tone too it but your ear has to be 6 inches from the tailpipe to here it! I have definitly noticed a horsepower increase but i really wanted the sound. I didn't expect it to rumble with a smooth running fuel injected inline engine but i didn't expect it to sound like a stock muffler.

-Jon

 

Btw, it is a 2 1/4" single exhaust. would it make a difference if i removed the factory resonator or cat? I am not adverse to removing the cat but i thought the flowmaster would let me have good sound and be legal.

-Jon

 

Lose the muffler and go straight pipe from the catalitic back. you have to keep the cat to be legal.

 

iamhakiem- New York doesn't require mufflers?