The machine - 1972 C10, rebuilt 350, HEI conversion, runs good and clean, burns no oil, doesn't smoke. Gets 18 MPG average. The story - It has always ran good. The exhaust is junk so I swapping on some old headers I have. I took out the plugs and they are some Splitfire plugs. The questions - I bought some plugs for the '72, R44T. Will they work ok? Will the MPG change at all? Should I exchange them for some R45TS? Are splitfire plugs worth the $$$? Side story - I have been away from dial up for a year and a half now. I'm using my mom's puter (dial up) for this and it really sucks. And yes, I voted! End of story.