What should I expect from 450hp?

[QUOTE=" I know.....let me guess. You're not gonna put 3.91s or 4.10s in it. [/QUOTE]

I do have a 489 carrier with 3:73’s, had these in with my 340. I was under the impression the extra torque of the 408 would more than make up for the gear change but not sure that it feels like it. I do a fair amount of highway driving