Header size talk ppl with expierance only plz

I'm at a turning point on my car
I have a 11:1 408 solid roller ,my car ran its best time of 11.2 117 this weekend

I have old Doug thorley 1 5/8 headers on it would it be worth it to get bigger headers on it or not worth my time? Ppl that have done side by side test or same thing plz que in thanks