Building a Renix motor for the sand

I just got back from 4 days at Pismo (oceano dunes SVRA technicaly) it was one of the most fun wheeling trips i've ever been on, second only to my rubicon trip early last summer.

The Cherokee did great in the sand, i have a few small issues to work out, but all and all my chassis setup worked pretty good.
when rockcrawling i never rev over 2000rpm, and the stock motor works great.
in the sand, i'm usualy somewhere between 3500 and 5000rpm, and could definately use more horsepower.

so i want to build a non HO (mine's a '90) that makes a little more than stock at the lower rpm range, and alot of midrange and top end.
i'm on a budget like everyone.
this is my semi-daily driver, my only street legal vehicle besides my street bike, so it would be nice if it were reliable.
smogable in CA

so here's the plan...
Borla Header - quadratec seems cheapest at $390
Carsound high flow cat
Dynomax Cat-Back
homemade intake with the filter on the pasenger side.
build a head and have it ported, milled, and a valve job done.
swap in a new camshaft, this is the part i have no clue about.

FYI the other specs on the jeep are:
6" lift with RE TJ longarms
35" MT/Rs
4.0L/AW4/NP231
D30/big shafts/lockright/4.88s
D44/welded/4.88s

looking for both general input and a cam recomendation.

I knew a guy in Portland, OR that had small block Chevy valves, springs, and roller rockers installed on his Renix head. He also had a header, and was not afraid of using the skinny pedal. It sounded very throaty, and he said it made way more hp on top end. Open up the Summit catalog and go shopping. Manley's has some undercut stainless valves that would be nice to use. They run about $90 for each set (8).

The HO head flows better, so I'd find an HO head and build that. I'd also go with an HO intake, t-body, and header, that way you can have the t-body bored to 62mm for flow. You must do the HO intake and header all or none, because of the EGR (the renix has one, the HO does not).

Steve

Basically you need to do all the mods that I've done to my 4.0 with four exceptions:

1. Install Mopar performance computer if you can find one. They're as rare as hen's teeth now but you could get lucky on e-bay.

2. Port/mill HO head with 3-angle valve job and regrind seats for Chevy 2.02/1.60 valves. You'll also need to ream the valve guides to accept these valves since their stems are slightly thicker.

3. Install Crane 260/272 degree cam (Summit Racing part no. CRN-753905) with Crane lifters and springs. This will shift the torque peak to higher rpm and produce more torque from 3000rpm upwards. You'll lose some torque below 2000rpm.

4. You'll need a 2.5" exhaust instead of 2.25".
_____________________________________________________________-

Modified 1992 4.0 XJ Laredo UpCountry, 170k miles, AX15, NP231, D35c rear, D30 front
Estimated 240hp@5250rpm/280lbft@3500-4000rpm
1/[email protected], race weight 3490lb
Future mods: 4.6L stroker
Website: Jeep 4.0 performance
Webpages: Electric fan, IAT sensor relocation, Intake manifold heatshield, Oil temp. gauge install, Jeep 4.0 cam specs, Jeep engine dyno graphs, Automotive formulae, CTS resistor trick, MAP adjuster

dino, thanks for the info, your webpage is invaluable, i have a few questions

the mopar computer - IIRC that requires running 91 octane... now that i think about it that would be do-able

would i be abneed to pass smog in California, so i need to run the renix borla header. do you le to swap on a HO head and still run the renix intake and header? i need to pass smog in California, so i need to run the renix borla header. do you know of any webpages for more info on the valve swap.

that is the cam i am leaning towards, will it actually make less torque than stock below 2000rpm or just less low end torque than i could make with a different cam?

if i did all this what would i be looking at as far as HP and torque?

thanks,
Jeff

If you want to wring out as much HP as possible, you'll need the HO intake manifold, TB, and header together with the HO head. Get the Clifford Performance dual outlet header for more high rpm torque rather than the Borla.
You'll definitely lose some torque compared with my setup from 2000rpm and below with the aforementioned Crane cam and big valve head but that won't matter if your gearing is shortened to get the engine operating at higher rpm.
Outputs should be somewhere around 255hp/290lbft with all the bits that i've mentioned.