** Just purchased a SM 420 for $100 was caked with 65 years of crud so could not tell a whole lot on condition on the outside. Spent it's whole life in a 53 3100, removed the side plate & looked really good inside with the exception of the granny gear had the leading edges of the teeth worn a little. Figured most of the SM 420's would probably show the same thing after 65 years as the 1st gear is not synchronized. **