355's to 391's how much does it help?

On my old mild 360 combo, going from 3.55's to 4.10's picked me up half a second (14.0 to 13.5). Optimal gearing is combo dependent...every one is a little different.
Sorry to bring an old trend back but I love this one totally agree a good pulling motor to 6 k the 355-410 will be in that range most the time