Do headers give you better gas miles and horse power ? If so how much ? (88 f-150 4x4 302 FI 5 speed 455 And still looks good)

 

i think they give more hp--how much i don't know--have to dyno b4 and after. i think most people who get headers aren't worried about gas mileage and have a heavy foot anyway.--lol

------------------
2001 F-150 4X4 Supercab
XLT 139" WB style side
5.4L V8 3.55 LIMITED SLIP AXLE
MODS:
AIRAID FIPK
SUPERCHIP(FLIP CHIP)
ROLL & LOCK TONNEAU

being installed as of 5/22/01
GIBSON CAT BACK
GIBSON HEADER
REFLEXX COBRA HOOD
STREET SCENE GRILL
HOLLEY THUNDER SUPERCHARGE
PILLER GAUGES