Sure grip

Hi guys,

I bought a 66 coronet 8 3/4 axle 741 open case for my 75 Duster. I also bought a 489 sure grip and green bearings. Now I'm broke, Ha ha! My question is, do I have to remove the thrust plug or can I leave it in? If I have to remove it can you point me in the right direction as to the removal of said plug?