I know the OP asked for 235 but my tired 49 216 in a 3100 is still mostly stock so I'll add it to the discussion.
49 mostly stock 216, 3 on the tree, single Rochester w/oil bath AC, single 2" exhaust w/round muffler and working heat flap, rebuilt head (at stock spec), stone stock bottom end, 4:11 gears, 225-75R-16's on stock wheels, avgs 12.5 mpg on mostly 40-45 mph runs. Gets a little over 13 mpg if I keep the foot out of it and avoid stop & go traffic.
Will be changing to a hopped up 235 soon.
