Re: pat\'s easy change
The answer depends a whole lot on the size you're buying, AND the amount of extension available in the PTO shaft.
Assuming your L3400 is the intended recipient, Pat's Cat 1 will extend the reach of the lower lift arms roughly three inches. If your PTO shaft was cut to the right length in the first place, a 3" differential should not be problematic. By example, my Cat 2 Pat's added four inches, and I still have plenty of reach on my rotary cutter PTO shaft.
//greg//