I put a new engine in my xj a couple months ago and it still runs like a champ but for some reason I just loved working on that 4.0 so I went out and bought another one off of craigslist with the hopes of rebuilding it I want to go bigger pistons cam all the good stuff but to be honest ive never done a "performance" build so I really don't know what kind of cam I would need or just how exactly to port the head and all that good stuff. Im pretty mechanically inclined and have no problem rebuilding an engine just not sure about the over sized pistons and cam. Teach me your ways!!

 

jeepstrokers.com

 

X2 Great engine site.

 

Usually the guys at the machine shop can educate you on what would work best. I trust my machine shop. They will bore, rebuild head and order master rebuild kit. Then you can put it together:-)