My brother and I recently bought a 2001 L L Bean Outback with the h6 engine for our sister. We got the car at a good (we thought) price as it needed an oxygen sensor (the check engine light was on), new tires, etc. We had the sensor replaced but the check engine light came right back on. With a little extra checking, we found that it was misfiring on the 1, 3, & 5 cylinders.I read about the same problem on this web site and a couple of people suggested that the guy should try sea foam. I got the aresol formulation and followed the instructions to a Tee. My brother then took the car and drove it "aggressivly" as it said to on the can to blow it out. It seemed to be helping a little until he punched it again and the engine died. We had it towed to a shop and were told the head (1 3 5 cylinder side) was bad. The shop quoted us $3900. to install a used engine with 106000 miles on it. We went on line and found a couple of used engines, one for $1250 and one for $1350. Now my question is how hard is it to swap out the engine and about how long should it take? I am a fair (shade tree) mechanic and have swapped a couple Chevy 350's in the past. I have heard the h6 is a hard engine to work on so am a little leary. Any advise? Should we sell it as a parts car and cut our losses?