I NEED HEAD... advice

It's engine rebuild time! I I am looking to up the performance of my 98'. Now I know the 0331 heads are prone to cracking, but are there any that are better than others? I read in JP Mag that the 95'ish flowed better for a few extra horses on OBD-II engines. Is this true? Any difference between XJ, ZJ, WJ and TJ heads?

What about power gains from different year/model cans and pistons?

I am looking for power gains below 3000 at most.

Thought about stroking it but would like to keep compression low so I don't have to run premium in 120 deg heat to keep it from pinging. I also read that they weren't holding up as long. Thanks

98 doesn't have an 0331. The Jeep 4.0L is old school responds well to old school hot rodding. Cat back exhaust, free flow cat, 60mm throttle body, K&N type filter, exhaust header, 4-hole injectors, head work, cam swap.

Shenannigans!

If you are going to bulid a stroker, fire up your google-fu...
Search Google: whatever you are looking for, naxja
The search here sucks...

Also, consider that more gear will net you more performance than any engine mod will per dollar. No need to go crazy, a simple refresh should bring back enough power.

That being said, your engine will be happier long term with a paper filter, especially if it sees much time offroad.

What is the smog situation in your area?

I know I don't have the 0331 casting I was just noting that I know to avoid it. Didn't know if any others were better.

Ya, not looking to go crazy, just want some added power. I already have a new header, opened up the pinched down pipe (plumbers torch and pry bar), performance cat, and cat back. I also opened up the air box a bit, and installed Accel distributor and ignition coil. It seems to rev easier on the interstate, but no noticeable power gains (still pulls hills at the same speed).

I have been running hot with lack of power for 3 yrs now and after replacing everything I can outside the motor, more than once. I figure my grief must stem from inside the motor. It has 133k on the motor, so I am hopeful that block is good, but I think I have a crack between the intake and exhaust valves in the head. Not sure though, truly frustrating.

So when I rebuild this thing in Feb. or Mar. I just want to make sure I do it right and have no regrets. I have meet people over the years with lifted XJs and 33's that could at least chirp their tires. I have never been able to break mine loose even when I bought it with the stock street tires on it 4 yrs ago. Plus my dads old 4.0 Ranger v6 pulls much harder than my Jeep and he is suppose to only have 160 hp and the same 225 ft/lbs.

At any rate I have been sticking with the paper filter, it does see way to much dust down here in Phoenix, AZ area. But I have considered AEM Dryflow Conical filters http://www.jegs.com/p/AEM/AEM-Dryflow-Conical-Synthetic-Filters/762071/10002/-1 heard good things about them and no need to oil, so you don't get that loss in filtration when it dries out.

Smog.... yep we have that brown layer all the time. It's not as strict as CA here, but I have heard stories both ways, some say they are picky others say no problems. My XJ being OBD II it has been smooth with no sniffer testing.

That ranger could be geared different than yoursand could weigh a little less.

91-95(7120) and 96-99(0630) heads have similar port dimensions. Most 0630s don't have the boss for the dash gauge temp sensor that was used on the <96(my 1/96 uses it and my dad's 6/96 uses it).