im deciding whichc serious to get cuz i know the 40 series have more power and are louder but the interior noise can get a little annoying but the 50 series are mellower. What do you guys suggest??

 

performance wise both are too similar to see any benefit in either... the 40 is louder.. i have a 40... i love the loudness of it... many people do not liek the noise... if you dont want it loud, get the 50... if you like it loud, get the 40....

 

how loud is it in the interior while driving?? is it bearable

 

again i will say if you like it loud then a 40... if you dont the nget a 50

bearable to me is not bearable t ooterh people.... i am part of the sound crew with a band, so my ears are tuned to loudness.... it doenst bother me..... however i have had passengers say that my truck is loud.... my boss knows when i show up for work everyday... he can hear my truck idle down his street.....

 

I have the 50 series, and is still fairly loud, with NO interior noise. I would recommend it, it has great sound, not poppy or grainy, but still distinctive and can be heard from a ways away.

 

do you have the 3.0 or the 22re, if that really matters. For me, when I do my exhaust, I am doing the 40 series. But I have the 22re and I like the noise.

 

Ive got a 50 series on my F-150. It has a nice, mellow tone. It doesnt sound like a late model stock car but you can still hear it. I would say it sounds good without sound obnoxious. It has a nice, V8 rumble to it, much like a musclecar.
You can hear it when you are accelerating but when cruising at a steady speed you almost cant hear it.
My brother put the same exact muffler on his '92 F-150 (302 V8) and his isnt anywhere near as loud as mine is. I think he should have gotten the 40 series because his doesnt sound much different than stock. It has a nice rumble to it but its not as if people look when he drives by. My truck on the other hand (5.4L SOHC Triton V8), when you drive by, people ALWAYS look. I like how my truck sounds when you fire it up on a cold winter morning. When its really cold out it has a nice bark to it.
Cap'n

 

I have a 50 series flowmaster on my 87 truck and I like it but if I had the money I'd go back and put 40 series on I like the slightly louder sound.