John,   Got the 60 I have been working on running perfectly and It drives well.  I will be restoring it this winter to show and pull (dead weight) in the spring but I wonder if you would answer a few questions for me.   I have decided not to bore the engine as it runs perfectly and holds 125# compression on each cylinder.  I do however need a few more hp to pull the 3200# class.   I plan on milling the head but what would you recommend to mill off?  I want the tractor to still be usable, dependable and run on regular gas.  I will also port and polish the head and whatever I can reach on the manifold.   Should I mill out the part of the manifold above the carb and to what size?  I still have the original MS 49 carb, Is this one large enough?  What carb should I be looking for?   Would turning the RPM's up to 1800 hurt anything?  Finally,  The generator will charge if I bypass the cutout with a jumper.  You mentioned in one of your posts installing a diode.  What would I look for in a diode and would that keep the battery from overcharging?    I realize this is a lot to ask but I really appreciate your help.      I have ordered the magazine with your article on rebuilding the 60 engine but have not recieved it yet.          Thanks in advance.   Dan Johnson