0331 head to... what?

[derf]

I'm getting close to needing to rebuild the 4.0 in my 01 XJ. I've already checked it and it has the 0331 head that is not stamped with TUPY. So I know that even though it's holding together at 180K miles, it can still let go. But I also have a rod knock and that's going to need to be addressed. So I'm looking at building up a stroker ahead of time and doing the swap over a weekend if I can.

I've been researching the 4.0 for a while and I have a handle on the different blocks and heads that came over the years. I've done some searching and I see that I can pretty much find any type of donor I want for a reasonable price.

I live in an emissions county in Colorado (and moving is not an option). I'll need to pass smog checks and that does limit me just a little. But it's unlikely a minor change like a head will even be noticed, much less the longer crank inside. So I do have a little bit of flexibility. Maybe even enough to get away with the Viper coil mod.

I am going to have to replace the cracked exhaust manifold so I do have the option of going with a different manifold to match something like an 0630 head.

My goal for this stroker is to have a reliable long term engine. I don't need tons of power out of it. The extra power from a mild/moderate stroker build will be more than enough for this vehicle. It's a driver that never gets pushed hard.

Is there an advantage to going with the 0630 head over the smaller port 0331/TUPY head? Are there better choices? Given all options on the table, what direction would you go?

[bleedsblue]

While I cant give you a lot of technical advice about which head will be better for you, I do have a 0331 Tupy head sitting on the floor in my garage that I am not going to be using if you find yourself making it next door to Utah. I am currently building my stroker as we speak. The block is at the machine shop. I have to keep my emissions as well so I am getting a worked over Tupy head from Russ Pottenger to run the stock cats.

Good luck!

[Russ Pottenger]

As mentioned a TUPY or a new 0331 head that I sell at $450.00 wouldn’t be a bad choice.

A 0630 Will work as long as you upgrade your header and fab up something to hold your coil packs.