What is the hp you make, what is the RPM band you want to remain in
What are the tracks you expect to frequent. . .
auto x. . .might want 4.56 . . .
You will nee to go buy a few more 489's, and still need some motor info.. a 2.90 may never ever fit any use other than bonneville, you may need a 3.90 as your shortest, you may need several centers, 3.90, 4.30, 4.56. . .and more