i was looking at putting a set of 27x10x12 and 27x12x12 mudkites on my 06 500 efi,stock tires r 26x8x12 and 26x11x12.wondering if these tires will kill my power or will i be ok with just changing a clutch spring or even getting away with the stock setting because the tires r only one size bigger

 

Height will be fine for power, but don't use the stock rims, the fronts will hit the tie rod ends.

 

you will loose a little power but not to bad. just use low range alot more in the bad stuff to save on the belt. koerbs is right as the 10" wide tires wont work on reg rims w/out spacers.