I run a 11:1 340 with an isky 510 solid, M1 single plane, 727, 3.91's and a 3200 stall with an 850 dp. on the street and it works fine for me. The vac sec carbs tend to be better for the automatics and better for street driving. I did have a 3310 (750 vac sec) on it at one point with a 484/284...