The 96 S10 that scared Laidoutvideo is mine.
Its a good truck,unless something kinda major goes out. And then your calling all the junk yards in town asking if they have a 96. And then you get, oh si. We have a 97. And then your all, no. I has to be a 96. And then there like, ya. 96 and 97 are the same. And then you'll be like, no dick face. There not!! And and at this point he just hangs up on you.
So I have came to the conclusion. Friends don't let friend buy 96 2.2 S10s.
But to answer you original question, the hydros won't affect the gas millage. Your right foot will control that the most. But I get 20 MPG around town with mine and 22/23 on trips out of town.