Tire size for easy steering
I was gonna suggest a roller bearing idler arm, but I couldn't find one for an a-body earlier than 67.
I've got a manual steering 440 rr with stock large diameter steering wheel, use 235-70x15, steers okay, 440 savoy with a smaller steering wheel, using 185 60x15s, primarily for the short height, also livable.
And agree with 273, see what you can do with an alignment.