Finally, this is for real.
Need a volunteer, you get the head for free.

http://www.edelbrock.com/automotive/misc/test-vehicles/

"Vehicle must be stock with under 50k miles."

Lol. That rules out about 98% of Cherokees.

2006 rules out 100% Cherokees.
Somebody must have a friend, family, neighbor with a 2006 TJ.

Ha. Didn't even acknowledge the years specified. Whooops.


So would a head designed for those TJ 4.0s work for our xjs? What would have to change if anything?

Head on 2006 should be the TUPY 0331... Meaning to swap one onto an earlier 4.0 would require an exhaust system change to the 50 state 2000 cast split manifolds.
When I owned a 2006 TJ I saw no real difference in the head from my 2000 XJ. The block and accessories were a whole nother matter. But we are just talking cylinder heads here.

Yeah only thing still running the 4.0 in 06 was the tj.I do hope they get one to use tho.

Just thinking what makes the most sense-
Aluminum, thicker deck, bigger valves, better combustion chamber shape, better intake and exhaust ports, slight 0.5 bump in CR. Optional conical valve springs.
Use stock intake, exhaust, rockers and pushrods.
Add +20HP out of the box.
Price? guess $1000-1200. Less $, like $700 would be great and sell a ton.

Only concern is alumn head/iron block and heat/expansion/cooling and reliability and head gasket problems.
Iron head/iron block is 200,000+ mile reliable, alumn head/alumn block is also good.

Adding 1.7:1 roller rockers and 0.043" MLS head gasket (vs 0.055" stock) to improve squish and compression ratio, could add another 15-20HP.
ECU SCT tune, another 10-15hp.

BUT all this gain might only be above 3000 rpm. Not exactly best Jeep power band. However, all the above would work great with a supercharger.

It will be their first inline 6 cylinder head i know of.But if anyone can pull it off right will be them.

I can only hope this works lol