Ill add a bit here. With my 350 and stock heads Comp 262 flat tappet hydraulic cam, stock iron heads, 650 Vac Secondary and 700R4 with 354 rear and 2 1/4 duals with Dart alum intake and stock convertor I ran a 13.7 to 13.9 all day long.
Now with a simple head change to AFR 190s, 3500 stall and Roller retrofit to Comp Cams XR282HR and 2 1/2 exhaust, and 750DP I ran a 11.91 best on all motor.
Heads are a big deal, then CAM, then Torque convertor in my case. I gained a .5 in the quarter just by changing the torque convertor!
Terry