Decent Slant 6 carb, intake, header setup

I have to ask why that slow in the quarter, I did better w/a mild Crane cam, 3.55's, 318 BBD, 6-1 DC header, stock valves........17.0's @78mph.......
what's up with that?
I'm thinking probably didn't dial in the motor with the rearend gears etc. slantsix' s need 3.55 to get up and go. But regardless have both a fast slant and a fast v-eight. Funny though when I pull up the v-8 car no one wants to race , it's always with my dart lol.