Alabama Cylinder Head turned off the lights and are no longer doing business.
I highly recommend Clearwater Cylinder Head.......they've supplied many heads for the 4.0 and get good reviews.
Without data, all you have is an OPINION!
Past Jeeps: '49 ******, '81 Scrambler, '88 Comanche
Current Jeep: 1999 XJ Sport, bone stock, daily driver.
I work on Jeeps!!