Fumblin,
I believe in addition to the extra 3 H.P. there was a slight difference in torque as well. However, I can tell you, my 46 with a 216 will run down the road smoothly between 45-50 at very, and I do mean very, minimal throttle.
The gearing in the rear-end, the skinny tube-type tires, and the poor stock brakes are all that keep me from cruising with the big-dogs.
With the stock rear-end, I have the same issues with my 250-I-6.
I believe the most obvious reason individuals would switch to a 235 would be to get out of the babbit/splash oiling/low pressure arena.
I'd be curious to know what other reasons I might have overlooked.
