You'll like that 261. The difference in power is more noticeable than might be expected if you look at the difference in horsepower ratings.

My questions regarding the 235 are not important (ignore them), but a 235 does not seem to have been an original option that was readily available from the factory on a 1/2 ton truck (or even on a 3800 - 1-ton truck).

Get you panel back together and enjoy the ride.