My cam would act a bit more mild in a 393. A rule of thumb I learned from reading Marlan Davis is that 50ci is worth about 8 degrees of duration (all else held constant). So, an equivalent cam for you would be something like 238 degrees of intake duration (at .050" lift) and 244-246 degrees on the exhaust. By that reasoning, a 232/240 duration cam (XE282HR) would have a milder idle than mine, and mine is just a little lumpy, but not bad at all. Acceleration off idle is smooth.