tti vs. hooker

I used my 1 5/8 headers from the prior 360 on my 408 for three years, always suspected they were a bottle neck. I did some trading and ended up installing the Hooker 1 3/4 units. Since the car is mainly used for drags, I had accumulated lots of timeslips to base the resulting change on . I gained an average of .4 sec in the 1/4 and roughly 3mph. Not all the gain were from the headers though, I had to ditch the P/S and go to manual to get them in. By far, the largest gain in performance Ive had with various upgrades to the 408 over the past 5 years.
My buddy did the same swap with his Dart Sport 360 after seeing my gain, we are figuring just a titch under .3 gain with his.
I know this didnt directly answer your question as to the step vs. Hooker 1 3/4 , but thought I'd pass it along and hope it helps someone out their.