kinda apples to oranges BUT,
My 425" ls1/7 hybrid has 260 cc heads. Should not have a problem with it being that soft on the bottom.Compression ratio, Localized port velocity and cam selection will play the biggest part in torque production on the low end.
There are tons of ls1 guys running around with a 250+ cc head on a 408.
The factory l92's are around that size also.
I think a 235 will be fine on a 434" engine.