Recently purchased a 1958 model 620. Tractor is in great shape and is mechanicly sound. Compression readings are 125# both sides. Anyway, when the tractor is first started and you take off in road gear, it feels like there is a pull to the left in the steering. If i let go of the wheel it will veer left. As the tractor warms up, lets say after ten min or so, the pull goes away and when you let of the wheel it will drive straight for a long ways.one finger steering at idle sitting still. Roll a matic narrow front. Any ideas? Also are front wheels stamped 1268 the correct front rims for this tractor? In the narrow postion the center rib of a 6.00 -16 tire sticks out past the frame, when wheels dished the other way they really get wide. When comparing the roll a matic to other tractors in my area,the wheels sit closer together, and the knees look thicker and more heavy duty. Could it possibly have a heavy duty front end on it? Or was something like this even available at the time? Thanks in advance!