I've been reading a lot of posts on several forums over the past few years, commenting on the plusses/minuses of different vintage tractors for different uses. When the subject of IH Cub / Cub Low-boy versus IH A, Super A, 100, 130, 140 for mowing and general use comes up, those who claim to have owned both recommend going slightly larger with the A, SA, etc. There seems to be a lot of people having problems with enough power for mowing with the cub. It seems that the power available is borderline at close to 12-HP. The larger A's have at least 50% more HP and that seems to make all the difference when mowing in less than favorable conditions. I would say skip the older "A" and go with the newer S-A, etc. models that have hydraulics.
Bill in CO