ROB - Yes, ductile, sometimes called Nodular iron is very good material. But gray iron can hold it's own too. Company I used to work for made ultra-high pressure reciprocating piston pumps for the food/chemical processing industry, also used them for the emergency backup cooling pumps for nuclear power plants... The cylinder block & head was 15-5 H900 stainless steel forgings, the machine base was class 30 gray iron. Two inch diameter 17-4 H900 studs held the block & head to the machine base. When something failed, the block or head failed, the studs NEVER pulled out of the gray iron base.
Gray iron machines nice an easy, just really REALLY dirty with all the carbon in it. Lot cheaper than steel too.
WAYNE - That style of wheel weight Charlie has is ANOTHER thing that company borrowed, or copied from somebody else. I bought a pair of used weights like that at a farm auction in about 1970 for $5/pair. They had NO sign of ANY paint on them at all, no markings, insignia, no part number, no trademark from the foundry that cast them, NOTHING. They had about a 20 year coating of rust and dust on them from being stored someplace around a livestock barn. I cleaned them up, painted them 935 white and everytime somebody say's there's that off-topic brand of weights I correct them.
Speaking of wheel weights, at PD #1, some guys were using front wheel weights from H & M FARMALL's for rear wheel weights on Cub Cadets. The H & M wheels had three 1/2" mounting holes for the weights, but the weights have two sets of holes, 60 degrees apart, the same spacing as the CC rear wheels, so they still fit fine with only two bolts, and weigh 42# each, and normally sell cheaper than the 26# CC rear or Cub frt weights. Plus they're thinner, so running 2-3 pair doesn't widen the tractor as much.