Re: 4.7 Headers - link provided
In over ten years of reading about the 4.7 I have repeatedly read that headers are not worth the effort/expense on the 4.7. The factory cast manifolds are an efficient design that are HARD to beat. My personal choice would be a custom y-pipe, high flow cat, and 3" exhaust.
The biggest gains in a standard 4.7 are as follows:
- HO cams
- HO intake or later design
- Single 3" exhaust
- A good tune
Why reinvent the wheel with headers other than to say you have headers? If you are going for max power then I would suggest getting another set of manifolds and polishing/smoothing the ports.
2004 Columbia Edition WJ 4.7 HO
RB4/Moog HD Steering Stabilizer/PML trans pan 10304/ Autometer trans temp and oil pressure gauge/UpCountry springs & OME 10MM Spacers/Bilstein shocks/Rubicon Moabs/255/65r17 Cooper Discoverer AT3/Factory chrome tow hooks/Mopar hitch & a loose nut behind the wheel