you will pick up some power how much maybe 30+ you have a good ex so your 1/2 way there so you not going to see alot with a cheap set of headers good ones abit more . but over all the iron mainfolds are not to bad the do not leak seal up good ,no burnt spark plug boots . you can re work the iron mainfolds and get them coated there work abit better .looks like your not really street racing it any ways ? there was a guy here in town that like to dress down his bbc with stock valve covers iron ex stock looking stuff