Steering box pitman arm puller recommendations?

[Sparky]

Can anyone recommend a pitman arm puller that fits the steering box in our Fiats? I got one that sounded like the correct dimensions, but I had to grind it down a bit to slip between the arm and the steering box.. and then it cracked .. and that was with the pitman arm being heated up. I'm worried that if I keep beating on this arm trying to get it off I'll be needing a whole new steering box rather than just the seals.