Log this reply as one of those grains of salt type replys as I have no experience w/a 235 to compare to the 216 I've put approx 13k miles on.
My 49 216 responds positively to every improvement I do it which keeps it in service in my mostly stock 49 3100. It has the std 3 speed tranny and 4:11 rear. It sounds and runs extremely well between 40 and 45 mph but gets real noisy at 50 and above. I've run it up to 65 to pass but don't keep it there long. I've never taken it on an interstate but have run a constant 55 for 5 or so miles without problems.
It's a low rpm torque monster. Sometimes I don't even bother to upshift to 2nd when going around sweeping turns.
All that said, I do have a hopped up 235 waiting in the wings when the 216 tires or goes out but for the present type of driving I do the 216 does an ample job of enjoyable back road cruising.
