has anyone done it on their 98 and up s10/blazer?? was there a performance gain?? what/ how you do it??

 

iwell my dad had a 95 s10 ss. and we port and polished the heads along with a chip and air intake and exhaust and it made the truck scream he did the port and polish after the other parts and it seemed to have significant gains my guess would be 15 hp maybe.