I would go with a square bore carb. A BG 750 flows very little more than a holley 750 with the choke removed. So buy the BG 750 you wont regret it. As far as a 750 Vacuum carb, well they are great on a heavy car with a tight converter and highway gear. On a car that is set up right a DP will kick its *** every time. As far as being told a DP will only pick up a tenth, well that may be true in some situations I picked up .3 when I made the switch. Now you have been told its worth .3. When I dyno vacuum carb motors, I have walked into the dyno room at full throttle and walked over to the motor and opened the secondaries by hand since the vacuum pod doesn't open the secondaries all the way. Worth quite a bit of HP in some cases. By the way I have 3 cars with 3310 Holley 750 vacuum secondaries. In a drag car, or hot street car a DP is warranted.