Tim,
It might depend on what deck you have.
The 18 inch front tire diameter just kisses the front edge of a fully raised model 46 deck at full steering lock -- I never thought that I could explain that unique set of conditions properly to my wife, so to be completely safe we just put the deck on the other tractor with the smaller front tires...
The large rear wheels/tires (26-12.00 x 12 on 9.5 wide rims) also come a bit close to the deck when up. I don't know how a 50 inch deck would fit, but I know that the 41 inch deck's anti-scalp wheels hit those same rear tires when they were on the 317 tractor.
Here is a full view of both 322 tractor stances with stock sized rubber on the left and the larger tires on the right.
Chuck