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

Very true. I learned at age 17 I hated cheap headers. So I just never compromise on that.

I think if you change headers and do nothing else and you gain 15 HP that’s a HUGE gain on a tuned engine. I lose sleep at night over less than that.

I was born a generation too late. Maybe two.

I agree. But, with many people, chasing that 15 horse maybe having to cut holes in my car i don't want to do isn't worth it to install them.
If i had a stock or super stocker.. heck yes