I don't think the straight six will have any weight savings over a bent 8 engine, but in general you'll have more torque... all things being equal. Horsepower is another issue though.
The 292 has a LONG stroke (I think 4.125") which really helps the torque, but not as good an engine to try to rev at high rpm as the 230 or 250 which have shorter strokes. Anybody ever work on a 2 cylinder Deere? These things have 7"+ stroke! The tractor pullers do crazy things to get even more stroke. They only run about 800 rpm max though... but they keep pulling hard right down to 0 rpm.
