This month I strated using mom's 1720, she like it over her 401 by far, I have to say it's 10 x's the machine a 401 is.
far above any other home machine I have, and I have almost all the common singers..
a local junk store has a 158 series for 25, case is yellowing but the inside and machine still look new, I would buy it. But am working on getting below the 20 count by winter ...
not sure what size motor it has, but in takes the standard type motor even though it is inside,,,