Ford Repair: crank shaft extension, 1996 ford tarus, crank shaft

Question
1996 ford tarus 3.0 I have already took off the crank shaft pullie. Ford has modified the new pullie so I also have to take the crank shaft extension off becouse it is built in to the new part. I know it has backwards threads. Is there a tool to keep the engine from spinning?Do you have any hits to get it off without risking rounding it off with a wrench?

Answer
jayson
   you may know more than i do about this one because i've never seen a 3.0 with left handed threads and i don't know of any pully modifications are you sure your old one didn't break and leave part of it on crank-an impact wrench should take it right off.