1 3/4" Headers Verses 1 7/8" on a Healthy 408....Is There a Big Difference??

I will bet it makes a little more power, but the roi in time and dollars? I dont think i would do it,(unless you HAVE to have a 9.xx slip, lol).

To be honest, i ran a 2"header with 3 1/2 exhaust on my 406. (Headers were custom, came with the car). 6.2x eigths, through the mufflers. Less motor than you, but LOTS less weight.