One of the first fiction hot rod car books that I read as a kid,(Before dirt was invented )was a story about two kids in the midwest in the mid fiftys that had model A and T Fords when they where in high school.One of them entered his car into a car show for a weekend, one of the other guys with a car in the show sold him and help install a Potvin "3/4" race cam for his 1948 Mercury flat head(they both had 1948 Mercs. in there cars) because the first guy had bought a "full" race cam from Potvin so he could go faster. As already said back then(when I was in Jr and Senoir high school) no one knew what the lift, duration, overlap or lobe centers where, let alone what that meant Lots of people "" " still don't I still have several of them "3/4" race cams that was ground last week by Comp Cams, do you want to race