Yes you might need a longer toplink... and in some cases, you may need a longer PTO shaft, too. Depends on what implements you are using... IF you need to use extreme angles on your implements (Most people don't) The box blade, to smooth out land, you would extend your top link to empty the dirt from the box, and "ride" on the rear facing blade to smooth out dirt... you might have a problem there...
There's a good chance you'll be fine with the top link you have.
PTO shaft should be roughly 6" over lap, 4" works (make sure you never bottom one out). you need to know what overlap you have now.
I bought a set of these for a friend, he likes them :
http://www.carterandsonsllc.com/ Oops, they are out of stock for Cat. 1