Don T - I don't recall if you have actually had this engine running again. If you have, did you re-torque the head bolts??? I forgot that one time and had a very small oil leak, replaced the pan gasket like you, replaced the breather gaskets although I couldn't see any oil there, replaced the O-ring on the dipstick, and eventually discovered the leak coming down the side of the head. Now, I only had a "mark your spot" drip, not a trail like you have. I also don't think the front or rear crank seals will leak unless the engine is running since the oil level is below the crank. I suppose it could be the cam cover you mentioned but I think you could see the oil leak there.
Jeff B - I believe the double springs on the PTO clutch is correct for your PTO. Not sure I really see any other possible mods to it. The button seems to be a little far forward but I believe it does work that way. As long as you're tearing things apart I'd go ahead and disassemble to make sure button is in the correct position. Next, I like that C-clip update to twisted wire. you know that once you drop that C-clip it's generally lost for good, and what the heck that wire is probably ok. Next, talk about carbon on the head and piston!!! Hope you got to it in time. You obviously need a new plug, and I would recommend the head gasket as well. And with the .010 over piston it must have been rebuilt already, so if you get her all cleaned up and make sure the timing is correct she might run really good. (see 169 posted in the Classifieds?)
Jeremiah C - see what I mean about carbon in Jeff's pics. Your 149 could easily look like that and that carbon can be very hard and get along side cylinder wall and score it among other things.
Hydro Harry
Old Cubs Never Die (but keep the carbon cleaned out, and the timing correct)