The reason you won't see much gain on the sohc is because the stock manifolds are pretty good. With the OHV and I think the 3.0 you will have a more noticeable gain than on the 4.0 SOHC. They mostly just make the engine bay look a lot nicer.

 

my manifolds are so old and beat up though that even replacing them with new stock ones would probably give it better flow...

 

My 4.0 ohv manifolds vs the JBA's

Maybe I got some mpg's maybe I didnt. I didn't notice much of anything.



Your looking at about 20% port blockage, all three are like that in one spot or another.

 

I put my headers in with one of my buddies last night. It wasnt too difficult...the only problem we encountered was that my EGR is now too short to reach the valve so we had to rig up a temporary tube so I could drive it home. Theres no leaks or CEL but this contraption was not made to last. Did anyone else have this problem after install JBA headers? How did you solve it? Im thinking I'll try to find like a EGR valve extender or something and if that doesnt work see if my friends at the local exhaust shop can weld me up a new pipe.