How much HP can one expect from headers and roller rockers for the 4.0?

Thanks,

Jake

EDIT: what will each mod add HP wise?

 

i want to know too!!!! although i really dont expect more than a few ponies if that

 

4.0 SOHC has roller followers from the factory, so nothing there.

Headers made a small but noticeable HP increase in my 4.0 as judged by the butt dyno. The stock manifolds are a reasonably good design so it may not be as much as you might think.

 

Thanks Bob.

 

any chance of getting some valve springs for my rx-7, or a radiator for my super beetle

 

iam tempted to do headers... did you have an exhaust already installed before the headers? i want to know if they will make my truck louder than it already is with magnaflow duals

 

no change in sound, just hp if any..

 

Umm I dunno - jsut ask Trev or Shane - with headers, intake, and a dual out flowmaster - my truck is pretty loud and nice and deep.. way more then a stock manifold truck...

 

thats what i am hoping for. i like how my truck sounds now but i wouldnt mind it a little louder

 

Headers definitely in my opinion change the tone of the exhaust. However not much on the power gains as others have been saying. However one disadvantage to headers is constantly having to make sure they are tight. Usually best to make sure the bolts are tight every oil change.

 

I agree. I noticed some from the butt dyno as well. I can't comment on loss or gain in low end, but high end is when they shine. My truck had been sluggish as of late and when the JBA's went on, I got some of that lost power back. Also, the sound they made sounded 'richer', more pure tone. Hard to describe in words really. lol.

 

It sounds like this without headers:

BraaaabrabrabrabraBraaaaaabrabrabrabra

With headers:

BRRAAAAAAbrabraBRAAAAAAAbrabraBRAAAAAA


See, headers help - they give you more capitals in your sounds!

 

ROFL!

 

I LOVE MORE CAPITALS!!!!!!!!!!!!!!!!!!!!!!!!!! MUAHAHAHAHAHA!!!!

 

Big cams give you Bold font with capitals. Methanol Fuel gives you the smell that makes it look italics.

 

lol italics are a good thing

 

braaaabrabrabrabrabraaaaaabrabrabrabraaaaaaa


Aggressive cam, machined .030 over, supercharged, headers, and a little wet injection - its so powerful it went so far past the caps it went back to lowercase!

 

lol

 

Trick I learned to prevent header bolts loosing up. Wrap the bolts with teflon tape before you install them. Don't know why but it works keeps them from coming loose and make them easy to remove when needed.
Cheaper than the high tech lock washers on the market and easier than safety wire.

 

I installed my 4.0 JBA headers using the original factory Ranger studs/nuts and the factory Ranger stainless steel gaskets. I heat cycled the headers twice immediately after the install, retorqued them once and never had to touch them again.

I used factory studs and gaskets because I bought the headers used and they did not come with the JBA bolts and gaskets. They were harder to install using the studs but, looking back on it, I think that is the main reason that I did not have any problems with loosening or leakage. I believe that the SS gaskets helped too because they make a more rigid installation compared to the usual soft fiber gaskets.

 

thats good to hear. once i install them i dont really want another part of the truck that needs continual attention