Originally Posted by extrashaky

There are actually two 0331 heads. The first one was offered on vehicles from late 1999 through 2002. In 2003 the 0331 TUPY revision was quietly introduced to solve the cracking problem. A TUPY head will have "TUPY" stamped into the casting between the #3 and #4 cylinders, right in the spot where the original 0331 head liked to crack. If the engine has the valve cover on it, you can see the TUPY stamp by looking right down inside the oil filler cap. To be clear, you don't want the non-TUPY 0331, but a TUPY 0331 is fine. The way you make sure you're not getting an original 0331 head from a rebuilder is to call them up and ask them what they're using. Get them to state unequivocally that they are not using original non-TUPY 0331s. Then check it when the crate arrives. If it arrives with a non-TUPY 0331, send it back. I don't think you can even get the crack prone 0331s new, so anybody using one would have to be installing a used one. Most engine builders are not going to do that because they don't want to risk having the engine come back under warranty.

Originally Posted by jeepdreamer

So if I order a remanufactured motor from someone, how do I make sure I don't end up with another 0331 head? What years/models of 4.0 will work with my 2001 that did not use the crap head??