Its been a while but I think I may have solved this without actually finding the problem! A while back I started having trouble getting the tranny into gear, so I tightened the clutch cable a few turns and it was better. Then, it happened again so I knew it was either the cable or the clutch was toast. I looked at the cable in all the spots where I could see it and saw no problems so I thought maybe it was a worn pressure plate. The plate wasnt that old but I remember burning it up a few times, (pulling someone out of a ditch, pulling myself out of a ditch, etc). So I pulled the motor but the plate looked fine. I went back and dropped the clutch pedal assembly and found the cable was in fact coming apart at the very front where I couldn't see it before. Great. So on a Friday night I pulled my motor and put it back in unnecessarily. Well, I needed the practice I guess. Since then the power loss has not shown up. I figure there was a bad connection somewhere that I missed when I had gone through before. The joys of bus ownership! I did do a little cleanup and rust patching while I was in the engine bay, so there's that.