Ok, i've been searching for the past week to get a general idea of where to time my 400 sbc, right now it's sitting around 16......but i keep hearing that 16 is ok, just as long as it's no more than 39 overall. What does that mean, what other numbers factor into the equation that i'm not getting?? Is it when the motor advances when revved? Also, how do I tell my overall number is? Any help would be great, I replaced the gaskets on the intake and after reassbembling the intake and dropping the dist. back in the 400 seems to be running hotter and less oil pressure, everyone that listens to it or times tells me it's perfect, but i still think i'm off somewhere....the motor seems sluggish on take off and at higher rpms. I really wish i could tell you my excat cam specs, but i have no clue......when i bought the motor the builder said something about .510, not sure for what though.....also i have an Accel HEI dist. edelbrock carb.