nice to see the cam isn't too big. I don't see it making power above 6000 in a 351 tho.

back to the origional question, you need to chose tire size then rear end ratio.

*I* am not a fan of driving on the 28" if i can avoid it....its not that much fun.
If it were my choice, id run a 26x10 and a 3.55 gear and you'll have a little room to get faster. IMO any more gear than that you'll be spinning your motor WAY more RPMs than you want.