cobrakillerta

iTrader: (3)

So I currently have a 2006 Grand Cherokee Overland with a 5.7L HEMI. I have a few mods such as a Volant intake, Diablo Intune, etc. As soon as it warms up I'll also install my Superlift 4" lift and 295/70/17 tires, skids, etc.


I know this is an LX forum, but I figured this is the best place for good engine tech.


I have the usual 5.7L leaking manifold/broken manifold bolts. I've contemplated upgrading to the stock SRT8 manifolds or even long tube headers in the past, now even more reason. I'd like to keep my spare so I'll either have a custom Y-pipe built to merge into my stock cat-back or run SRT8 style duals and dump it right at the rear axle if I somehow can't get both tailpipes to squeeze out and exit at the stock passenger side location.


I know a few guys have swapped the SRT8 exhaust onto their 5.7L's and even a few header swaps have been done. The header swap actually seems more straightforward as apparently it clears everything with no modding except for the EGR notch.


Unfortunately I have to keep this on a tight budget which is what has me looking at stock SRT8 manifolds, OBX or possibly a used set of quality LT's such as ARH, etc. I know OBX is cheap Chinese stuff and I've learned from my years of modding to 'Do it once and do it right' but, honestly the truck is only my daily-driver, now has 90k miles on it and I'd like to get back into an LSX car in the near future (had to sell my last car to buy my house).


My main question is, would there be much to be gained going to long tubes over stock SRT8 manifolds on a bolt-on 5.7L or would I actually be hurting myself by doing so?
If I did go with long tubes, does anyone have any input on either running stock SRT8 cats vs. OBX cats vs. other high flow cats?


I did come across a set of ARH headers with cats, but they have 1 7/8" primaries. Would a 1 7/8" primary be way too much for my set-up?


Keep in mind I will get an appropriate tune through a reputable tuner (Johan, HEMITUNER AJ, etc.) after I do these mods.


I'll probably also have my TB ported/polished, any real gains to be had in that?

KingKoser06

I'm a recent believer in modern HEMI power, but i do know a lot about engines in general. I don't know anything about the flow of the SRT8 manifolds, but I do know that a good set of long tube headers will flow really well, and sound good. i know on most applications that you will unfortunately need to redo your whole exhaust system, costing big $$$. I don't know if you need to do that on your car but coming from the world of Mustangs, that's what you need to do. and if you do go with getting a set of long tube headers, i would highly recommend that you go with some kind of ceramic coating. the chrome look good, but they rust like your stock manifolds tend to. I hope this helps man. and like I said, i don't really know how well the stock SRT8 manifolds flow