I removed one last weekend and all I did was put my large crescent wrench on it and gave it one good hit and it came lose, this was on my sons 05 f150 with a 4.6.

 

Finally got the thing off. Had to go to Oreilly's and get the tool. Still had to put a big wrench between them to get it to pop loose. Guess the guy that put the long block in years ago didn't want it to come loose. But at least I took a pic of the tools so I know what size to cut the big square notch to catch the water pump bolts next time. That was the only thing I really needed. Next time I'll just take a scrap piece of 1/4" and cut the square with the torch... instant tool!