ditto on the k5 fan and new heater core. also make sure you replace the t-stat with the right one(195). the beauty of the cj dash is that it is just a flat piece of steel..get an uncut one and you can put whatever gauges you want in it, i don't know anything about xj's but i'd imagine switching heating components would be a nightmare.
the head swap isnt a bad idea if your 258 is healthy, plus you wont even have to take the engine and tranny apart. what tranny does the cj have now? if you have a t176 you're all set. t5 or t4 ..maybe. you cant just swap in the xfer case unless you want to flip it and make shifter mods, plus the dana300 is better anyways. if you want the whole 4.0 liter then keep whatever tranny is attached to it and get a clocking ring for $160 to hook up to the dana300. leather seats in a cj is a good idea (think heated), i just dont know how they hold up to rain.
good luck, take alot of pics and do a write-up on it
Brian <img src="/forums/images/graemlins/smile.gif" alt="" />