Mike: Yeah, I'm trying for maybe a 95% tractor. I don't want to be an instrument of confuguliation, or become one of those "Previous Owners" of whom people say, "Can you believe what this guy tried to do?"
It just isn't the right head for the application!
I think I'll wind up putting the old head back on, after I figure out how I want to repair it. I can understand why Dennis chose to re-tap for a larger plug --there just isn't a lot of metal there to work with. But then too, if I can find a Heli-coil to fit, I wouldn't have to worry about aluminum threads for the spark plug anymore.
Doug: Thanks for chiming in. I'm thinking that the head was originally intended for an earlier model Cub that featured the gas tank over a major portion of the head, with the battery behind it toward the dash, and the voltage regulator in front of it, also in the engine compartment. That would mean that it would have originally been designed for a 147. I don't believe the head was intended for non-Cub application; it came from a forum member who was getting out of the hobby and selling all his "stash" which included my head and several other items. He didn't identify the model number for his parts, simply the engine size. I may contact him to ask if he remembers or knows for which tractor the head was intended.
Harry: Some say that "God is in the details" others say that "The Devil is in the details." All I know is that the details can be-devil me because I feel that somehow God is watching. I really don't want to grind on a perfectly good, and possibly rare, head just to "make it fit." Neither do I wish to cobble disparate tin pieces together to create a heretofore unknown configuration. I will post a closeup of the fit-up issues I foresee if the current High-Boss head is retained. (Psst, Doug: I'll show you mine, if you show me yours --just kidding.)
I'll tell you all one thing, though, I'm mighty tempted to re-use the head gasket, despite the fact it has been compressed: it's still fresh, and I would think it would retain its holding power with the proper torque.