The width of the tire is of no concern as long as there is proper clearance. You have to measure the outside dimension. It has to be really close to the one you are replacing or the ratio of front /rear drive is going to be off.
I would pull a string around the 8" tire and compare the length to the 10". If it is within an inch or two I think you would be ok. The ratio is designed so that the front tires run a little faster than the rear so they are always pulling forward a bit on the rear which is one of the reasons why the fronts wear faster than the rears.