I gonna be putting on this tuesday new exhaust for my truck I have a 2000 F150 4.2 v6 auto with 3:55 and an K&N.
The Exhaust system im putting on is a single in dual out 40's flowmaster 2.5inch 14 gauge aluminum wall and strait out the back with three inch angle tip chrome tips. My whole question is wether or not there will be enough back pressure, or will I loose any of my low end torque, witch I would not like.?!? If anyone knows a bit on this please let me know and if there is any 4.2 guys out there with an exhaust mod please put in a reply with your creations. Thanx

 

This worked well for me. When I was writing my check for the work at the exhaust shop, I was amazed that the engine I heard revving in the garage was mine little 4.2L. I attibute the tone to the 4" tips. When I pulled out of the shop's lot, I noticed that my truck did't feel as heavy any longer. The low-end power was definately improved. Although others have gone with 2.5" pipes I beleive that 2.25" keeps the back presure at the proper level for a SI/DO setup on our 4.2L's.

Are you looking for advise or did you already purchase all the parts and just need a bit of reassurance???

 

just wanted to find out if this was the wright move before i fork out 369.00 to do this i just wanted to make sure i didnt sacrifice speed for sound, I would rather have the speed...
Due u think I wuold loose any gas milage or any thing at all by doing this and what should i expect to gain?!?

 

i have the same, 4.2v6 2000 f-150. I brought mine to a meineke who installed the fm 40's si/do setup. he cut right behing the muffler and installed the fm there. and ran the two tails out the back. he also put on the slash cut angle tips. but after he was done, he started it up, and it actually sounded pretty mean. it wasn't a low rumble but loud grumble. it is noisy inside the cab a bit until you hit 55. But like 45-50 and 60 -70 it starts getting loud again. You can tell at certain speeds,but you will definately hear it inside the truck. i gained some mileage because i have to drive to broomall pa once a week and test the mileage it is about 100 mi from home to there and back. torque has increased a bit. I am very satisfied with the results and should have done it when i bought the truck. I wanted to wait for the warranty to run out before i changed anything but i figured those stock mufflers will never rot out. well, i hope this helps you out.
steve