I run a .030 over 440 with 10 to 1 flattops, pocket ported heads with .509/312 (advertised) cam, headers, 4-speed, 3.55 gears and two 500 cfm Edelbrocks. Very streetable, lots of low end grunt, no problems at all. I have run the Woodward Dream Cruise numerous times and other than my clutch leg getting tired, it was no problem at all. Granted, with the cam it still lopes up to 50 mph and the mileage is not great at 10 mpg (babying it). But, I wouldn't hesitate to tunnel ram and two small fours on a big block. If you were running a 727, you would need loose converter or a much less radical cam.

I have also run a 340 with the same basic setup and it wasn't any fun at all! Not enough torque, a bit like a two-stroke dirt bike. It was either "on the pipe" or not.